I feel so guilty all the time?

I hate it, I feel guilty all the time about every little thing. It's to do with my bf really. If I look or speak to another guy I feel guilty and its starting to affect the way I think. If I think certain things I feel guilty too. Also if I think something bad I have to do touch wood knock on wood like ten times and I have to check things loads eg if I plug something in. I try to stop it but it's hard, do u know how I could stop this or what it is.