Raised by an abusive mother who took every opportunity to tell me how worthless I was, I know what it's like to grapple with those sort of feelings. It took a long time for me to discover my own self worth. I strongly urge you to seek out a therapist. It's one of the best things I ever did for myself. Just having someone to talk to, and voice those feelings helped me work through them and the prescription anti-depressants helped too. It gets better, believe me.