I will suggest that your experience represents a form of suicidal ideation. I felt that intensely once. I can give you details, but it came from a sudden cessation from taking Prozac. The specificity of suicidal ideation took me aback in a way I would not have expected was possible.

My understanding is that people who suddenly stop SSRI's experience suicidal ideation and can proceed to kill not only themselves, but kill their loved ones. (A religious coworker lost her parents to murder-suicide with Prozac as the suspected culprit. She was interviewed in a Scientology anti-Prozac documentary. Her father was a pastor!).

If the feeling persists, consider taking these supplements as needed: L-methyl folate, 5-HTP. Discuss it with your clinician if you have concerns.

It happens to all of us,I had a similar feeling a week ago on Sunday. Out of nowhere,there was a surge of despair that I didn't see coming.
Luckily,that passed as soon as it appeared.

It is a very human way to feel, we all get days like that. It does help us to appreciate the good days. When the sun is shining and there is a song in your head.

We have this one life, every experience and feeling has something to teach us. Everyone has value including you and me. Talk to someone you trust if the feeling persists. One thing I do is write out my feelings then go back a day or two later and read them. I learn a lot about myself that way.

We are here and you matter to us. Take care and be kind to yourself.

We mater in ways we ourselves can not fathom. For one you are certainly valued highly for your contributions here, which means, that a lot of people get a lot of joy thanks to you, and that is no small thing.

Perhaps when we look for the point is when we miss it, because we say. "IS there a point, or am I just here for the ride ?" Yet then, we miss the all important fact that going on the ride, probably IS the point.
"Give me no more than a pot of cheese, and I will feast." Epicurus. By which he meant, look to simple things. Have a mug of tea sitting under a tree, and listen to the birds while perhaps talking to a friend. Then remind yourself that, if you were not there, the tree would not be appreciated for its shade, no one else would hear or value the birds song, nor would your friend have you to talk to. All of those things are unique experiences and contributions, that no one but you could have in all the history of the universe. Without you, none of those things could happen.

That is why, learning to value the small things, is not only the best way to happiness and contentment, but by great cosmic irony, almost certainly, the biggest and most important thing that we do.

Also listen to all the other advice that the members here, like Charles below, give, it is usually good.

I think everyone probably feels that way every once in a while. Personally, I don't really think there is a point to it all. Its simply whatever point you decide to give to life, if you so choose.

But, if this feeling returns or persists, then you may wish to speak to a therapist. You might have some low-level depression that you've never quite noticed.