birkin I used to feel like that, and then now I still feel sorta like that but for very different reasons, and my behavior isn't as dysfunctional as it used to be.
I used to get blamed for all sorts of crap because I didn't speak up. I used to do almost anything anyone ever wanted, because I was raised to comply with requests. Even when it didn't feel right, I didn't have a picture of how else a person could act. I was gullible, silent, assumed if anyone was wrong it must be me, etc. I definitely felt (if I let myself examine the issue) like I had something wrong with me and that others might be doing me a favor by tolerating my presence. I would put almost any human ahead of my own needs and preferences, and I got taken advantage of a lot.
Now, I just try to do the math. It usually works out that I am still willing to be a glorified coatrack or give a comfortable person the shirt that I need, but if my suffering in the act is less than theirs would be without my action, I don't mind. I guard my dignity carefully and whether I feel good about myself or not I usually am able to keep other people from being the arbiters of my identity. I've had to really methodically cut out or keep away people who abuse my desire to avoid cynicism, though.