I completely understand how you would feel like that because I was raised in a very strict Christian home. That is what religion does it makes you a prisoner in your own mind. It is hard to overcome at times but remember any religion out there is meant to make you feel this way as a way to "bring you back to the truth." Don't fall for the lie and don't feel bad, feel free!!! Hope this helps.

Study. Read the Bible (all of it). Check out the Skeptic's Annotated Bible/Koran/Book of Mormon. Study history, science, everything.
Morality does not come from religion. Don't fall for that. Study the Euthyphro Dilemma (why morality does not come from the gods; Plato).
If you experience discrimination, that will help you reject your own discrimination, and learn to accept people for their universal humanity, desopite their being different.

You shouldn't feel bad...but that is easier said than done. It takes time. It doesn't happen over night. If you had several years of indoctrination, then you have a lot to overcome. The best thing to do is to remind yourself that the person you are, today, isn't different than who you were before you chose to be an atheist. Yes, you have chosen to no longer believe in gods, but the essence of who you are has not changed. If you were a "good" person before, you are still a "good" person now. The same goes for you, if you were a "bad" person.

I put good and bad in quotes, because they are subjective terms. They only have the power which we choose to give them. Of course you can realize that the things you did as a believer, that you thought were good are now bad. And vice versa. No worries. Just try to be the best person you can be, and that is all that matters.

It is a bit frustrating being atheist when your family is not. Thankfully my siblings (all younger than me) took my lead and are all atheist too, but my mom and grandparents seemed to become more vocally religious the longer us kids stayed atheist. Mom is still very active in her church, in fact more fanatically so than when we were kids, and we feel a bit sorry for her that she is so invested in the delusions of her religion that she can't imagine being ok without religion. The more time you spend immersed in the company of family who think being atheist makes you bad, the harder it will be. The best solution is to shift your focus to people and activities that remove you from the company of those inconsiderate people who are making you feel bad about your atheist stance. "Own" your own beliefs and opinions, develop explanations in words for what you believe and why, and then focus on the topics and activities you enjoy, rather than constantly re-rejecting the beliefs and lifestyle you have already decided you do not accept.

I have never felt bad since i left the church.I am very confident in my new worldview.

I wish I could be more helpful here, but I don't understand why you would feel bad about not believing a lie. I value knowing there is no Yahweh standing over every second of my life taking notes preparing my place in Hell. Hell isn't something I fear. I look around in amazement at all the incredible beauty this world has to offer and I give no thought to Yahweh. The story is clearly fictional and I'm a good person, just as you are. Neither of us is perfect but that's a good thing.

Perhaps on a certain level (subconsciously), you seek acceptance from your religious family. Even though you find atheism gratifying, there may be a void that has yet to be filled. I encourage you to consider/reconsider Maslow's Hierarchy of Needs, [simplypsychology.org]
and evaluate what area(s) may currently need more attention. Best wishes, and I hope this helps.

why feel bad in your belief? just "keep the faith" and be confident in whatever it is that you believe in

Face and accept the good parts about yourself. It took me a long time, not because of believing or not believing, but because the levels of demand for sacrifice I was raised with were just crushing; nothing was good enough, and I had to learn to re-calibrate my expectations of myself and others. You don't have to believe stupid stuff to be a good person. Do well and right by yourself and others as honestly as you can, and that's about it. You're a good person. Give yourself time and remind yourself of it occasionally. It does help.

I have to say that I must have been fortunate in that I never had such thoughts about my decision to adopt an atheistic viewpoint.

realize that you have nothing to be ashamed or feel bad about if any thing you should be angry at those who lied to you and told you that Atheist were bad or dirty you owe them no apologies you are free now don't let their prejudice define you.

We all have been brainwashed to believe the lies. Was difficult for me to tell myself --there is no god, slowly my eyes opened wide. No one is a bad person, just because some idiot or idiots thinks so. The more a person hears a lie, over and over, and over, the more is going to believe it. Christians are victims themselves, They do not have an idea what has happened to them, brainwashed made them very stupid.

Stop being a coward.

It is hard to stop those feelings because now I'm so different from most people in this very religious area I live. Very nice people live here but I can't identify with them because I have to listen to certain and regular religious comments. I was thrilled to KNOW...but then I have become isolated. I always heard those "bad" words like infidel, unbeliever, atheist, referring to the type I person I now am...I do know I am a good person and I do good things, but in the eyes of the "believers" I am trash.

"By their fruits shall you know them." It can be rough disappointing family, no getting around that. However belief in a supreme being is not necessary to lead a good and caring life. If you strive to help the helpless, clothe the naked, feed the hungry and shelter the homeless you are a good person. No belief in god(s) necessary. Ask yourself how belief in a deity would change your actions and attitudes toward others. THEN decide whether or not you're a good person.

It takes time, and a lot of talking yourself out of what is basically stockholm syndrome for 'unapologetically stupid people wearing smiles and fucking everything up'

I know just how you feel. I was brought up as a devout protestant. We went to church every Sunday, I did the confirmation thing, and kept the faith for over half my life thus far. It's no small exaggeration to say the moment you realize you've been raised to believe in something that isn't true is quite traumatic. I felt the repercussions for quite some time. But eventually, the remorse fueled by guilt and shame faded and was gone, as it will be for you in time.

I don't fell bad/sad about it. I do feel sad for all those who do believe and give away a lot of money which they badly need for themselves.

Not sure I understand what you feel badly about. If you don't believe in a Higher Power, then you don't believe there will be any punishment for your nonbelief. Maybe you're more agnostic than atheist? Not trying to be disrespectful of your feelings!
Help me to understand...?

Embrace your enlightenment, you are still the same person good or bad nothing has happen to you other than you have shaken off the chains of delusion. If other choose to not accept and approve of this that is not your problem it is theirs. Your happiness is not dependant on others it is only dependant on you.

I was raised by very serious Christian parents.. but for me it never added up and I never believed the Bible stories I was taught. I took a real liking to nature at an early age.. that might have been part of it. I was not rebellious to my parents .. that had nothing to do with it.. I actually desired to please my parents. When very young, even ‘prayed’ to be shown a sign, something to make me believe. I received no answer. I attended church and Sunday school every Sunday until I had a drivers license which meant... camping almost every weekend with my friends.