There's always a reason to keep going, no matter how small. For me it's my dog, but it could be as simple as ice cream. It doesn't make the feeling go completely away, but it helps.

Think of your family. Your friends. I want you in this world. I suffer from the same things. Talk to a therapist or meditation

I struggle with not wanting to exist as well. I have been on pages upon pages of antidepressants and mood stabilizers and anti anxiety meds for over a decade (I stopped recently) and even on half the meds it didn't get much better. The most I can do is "I have to exist bc my dogs wouldn't understand" or my family (parents, husband, what have you) would be distraught. I'm going to try therapeutic psylocibin soon, I think. Its just so hard- everyday- wishing I didn't exist. Maybe antidepressants will work for you? Maybe an alternative therapy (ketamine, MDMA, psylocibin etc) done in a controlled and not recreational manner? Idk. Wish I did. I'll post if I do the psylocibin to update.