So introverted that the mere idea of going to the grocery market seems taxing...
I agree with the earlier poster that your interests and activities are not those that are usually associated with an introvert. I am in no way qualified to give a medical opinion, but I will suggest that you do some research on Social Anxiety Disorder. It is very common, and is treatable with medication and therapy.
If this describes what you are feeling, you should make an appointment and discuss with a medical professional. I have been treated for SAD, and feel much better for having sought help.
I love to shop, so I don't mind going to the grocery store. What irks me is the presence of so many loud, poorly-supervised kids running around the store and wailing for their parents to buy X, Y, or Z. I tell my students that I am convinced that places like Wal-Mart must give a secret discount to families with a lot of kids, because why else would you bring five kids with you in the first place?
Sorry, got off-topic (that happens a lot). I'm with other folks -- when you can, get someone else to do your shopping for you. There's a service in my area called Shipt (they were just bought out by Target). You pay a yearly fee to become a member, you use an app on your phone to order groceries, and they bring the groceries to your door. Here in my area, an order of $35 or more incurs no delivery fee, and they will even bring you alcohol. (No prescriptions, however.)