Dwindling

Feeling small. Feeling...less.
Ever since I was a child, I have felt a little less deserving of, well, anything, than those around me. It may be a function of my depression. A consequence of childhood bullying. A leftover from religious indoctrination. A result of emotional abuse. I don't know if the ultimate source really matters, but I don't know how to deal with it in the present.
Mostly, I withdraw. I hold back, stop talking about how I am, how I feel, what I think. I still make small talk, crack jokes, exercise my sarcasm.
As soon as I think people are tired of me, though, I stop. I stop commenting and liking and sharing posts on social media. I stop giving my opinion when I don't agree. No one gets the silent treatment from me, but I shrink back from the world just a bit more.
It is partly that I don't want to be a burden, don't want to seem whiny or weak. Don't want to join the hardship contests, or overshadow someone else's story or needs. I don't really like being the center of attention anyway.
But at the heart of it, it is mostly that I don't feel that I deserve the attention, or sympathy, or help. Others have worse problems than mine. Other people are going through real crises. I am just a fake, a coward, I don't deserve help. I don't deserve love. I don't deserve anything. My needs aren't important, or urgent.
And yet, I always talk about how everyone is worthy. Everyone merits respect, consideration, to be heard, to be loved. Everyone is needed. Everyone matters.
How do I learn to feel that, really feel that? How do I make myself believe in my own worth?