It's tough when people act like that, isn't it? You really might do better by not focussing on them, but onto yourself first. If you are truly doing your best for right now, how can you do anything more??? You can't. But you can work on how you feel about yourself, which seems at a big low in your life.

God loves you. (I'm reinforcing this for myself right now too)
You are worth His love.

Are any of us perfect? Nope. And you see that in other people too, right?
We don't have to be perfect for God's love.

Maybe come up with a few "come backs" that aren't offensive, and you that you can deliver with a smile (fake it till you make it?) when someone says something that just isn't true (or no longer true)? "God loves me." "USED to be." "I'm not that way any more." Are possible phrases. While you begin to reprogram their thinking, you will also help yourself to change your way of thinking about yourself.

Quit repeating the nasty things they say. Reframe the things you find yourself thinking that are negative. ("I really don't like myself.... BUT I'm working on liking myself."