I know this is going to be hard to do, and easier said than done, but I don't think a lot of your problems will be resolved until you learn to stand up for yourself. Your human dignity is worth you telling people when they are wrong sometimes, if they have done something bad toward you, and if their behavior was unacceptable. It may mean reducing some of your social contacts at time, but it's better to socialize with people who will treat you like a person and not someone they can just discard.

When I was younger, I did a lot of suicidal ideation and it wasn't until I started putting my foot down where I gained a stronger sense of self. I had to do this with my family of all people, and it wasn't until after I moved out where I began to feel whole. YMMV, but I think a lot of it has to do with knowing what the first steps are to take to begin that process of healing.

I've been to therapy too, and after a while I realized I don't need more therapy, the solutions are already set before me and it's just a matter of me taking the first steps. Therapy is designed to help us identify our needs, sort through our issues, and give us the tools to recognize the steps. No one can do it for us but us.