What is happening to me?

The fact is that my problem is a little more complicated. In the end, even though I somehow realize there might not be any problem I am still not sure and continue to search for answears. I think (but don’t know for sure) that I suffer of obsessive compulsive disorder. I find this problem a bit more delicate… I have a sick feeling well a girl-friend (but no relation) of mine is pregnant through petting. I didn’t even come or anything, just the fact that I didn’t knew if I somehow arranged my… in my pants and took some seminal liquid on my fingers drives me crazy - but I somehow kinda catch the irrationality of this thing because I didn’t just put my hand in my pants and after between her legs. I just got to bed, started kissing touching and things, undressing etc after that I tried to give her pleasure. So seems kind of irrational knowing that even IF there were sp*rms on my hand I think they wouldn’t have resisted in air. I said I will chill after her first period comes… ok it came and I was chill about 1 week, then everything started again from the start and I started to get paranoid about the same sick feeling. In the meanwhile (after like 2-3-4 weeks after the event) she had to go to a gynecologists because her periods were unregullar in the past and the gynecologist told her everythings ok with her only she is very unregullar. I said I will chill now because she went to the gynecologist and that would be fine. But after 1-2 weeks it started again. I said I will chill after her second period after the event, so I was ok 1 week then started again. She did a pregnancy test only for me, which was negative - I was ok 1-2 weeks then I was bothere when I found she had close periods (but this should have been because she’s unregullar) like at the start of the month, at the end and again at the start of the next month. So 2 months almost have passed since the event and I still don’t know why I can’t get over this. Even though I seem that I realize my problem, I still have to continuos need to get a certain answear from someone. I can’t go to a professional help because I live with my parents, don’t have enough money and they wouldn’t understand my problem. I always think of posibilities: I have heared that there can be periods over pregnancy (why would she have periods so close?! - annoying thought), or about the fact that an extrauterine pregnancy (wouldn’t be detected by a pregnancy test), or about the fact that she might not observe pregnancy simptoms (as I know, some women observe these simptoms only after a while) etc. I would like if some people could give me a piece of advice reffering to my both issues (meaning this girl and meaning this disorder I have (if it is a disorder)), or inter-connect. I don’t know what to do anymore. Some well-constitued help would be really apreciated, because I think this is going really crazy now… Thanks.