I feel worthless. Can anyone please help me?

I can't cum during sex. I don't know what my deal is, can maintain a chub, but that's it. I can't even accomplish a full erection. I feel sexually aroused during it (I'm a bottom) and always enjoy it. I just feel completely worthless in bed because of it and like I disappoint everyone I've ever been with. They think they are doing something wrong and feel bad, which in turns makes me feel like complete shit. Anyone had this problem before? It's really starting to put a strain on my relationship and my emotional health. I just want to be normal.