Okay, I've waded through the whole thread (whole cup of tea!) and gone back to the start. Cos I read it that, when your t says that people do like you, and care about you, she probably means her. She's not assuming or implying that anyone else in your life does, she's just saying that she does. Might be way off, but that's how I have read it.
Re self injury...owwwwwww....hugs and germoline.....I do the sleepy bit after too. My friend now takes a sleeping tablet when she gets SI urges and sleeps it off, might be something to try?

I hear that you say no one likes you, and you don't know why. Whilst I'm sure that's not true, I'm not going to argue with you. I live thousands of miles from you and I've never met you. I guess if it was me, I might think about joining a brand new group, when I feel up to it. Maybe an art class or something? And say exactly what you've said here, I struggle to have friends, I feel I'm unlike able. I'd like to change that, but I can't til someone tells me what to do differently.

I'm also thinking of people I don't like, and why I don't like them, friends I've avoided...
Ummm, I avoid one friend because she talks about her self all the time, non stop. Witter witter. Ummm, another one is very melancholy, everything is miserable....and one is just really hot and cold, either on the phone wanting to have lunch like NOW, or don't hear for weeks.
Don't know if this is helpful. Probably not just trying to be constructive.
One of my old friends ignored me, and I asked her why, she said it was because I talked about people behind their backs. I did used to, and I consciously changed that behaviour. This was years ago, I don't do it now (so much), although that criticism was devastating at the time, I'm grateful for her honesty.
I guess I'm saying that, I understand the confusion of not being liked, and I know it's not always helpful to be told that you are liked, if you still feel something is going wrong. I'm sure you are very likeable, and loveable Hazelgirl, and I hope that you find someone special who can show you that.

Xxxxx