Guilty after orgasm

Ok so I've been single for a while and therefore haven't experienced it for months but it's just really been bothering me recently. Every time I orgasm i get this sense of guilt after and I feel "dirty" in a sense. I always felt great leading up and would want to orgasm but then as soon as I did I just felt less sexy and felt stupid and guilty and I don't know why. The guy I was with (the only guy that's given me one) was fine and I cared about him so I don't know why I felt this way. Any ideas?