LOW LIBIDO/NOT FEELING MUCH/NOT MOANING

I need help. I enjoy sex the most when I’ve gone a long time without it and it’s all built up, but I’m in a relationship now. And I can’t orgasm, only with oral. My boyfriend is big, so that’s not the issue. It just doesn’t seem like a lot of stimulation. No matter what he does, I’m just not into it. I don’t think it’s him. Any suggestions? I’m relatively young too to have these sort of problems (22).