Worried about having committed a crime with my girlfriend

I think I have a form of OCD to do with having committed serious crimes like with my girlfriend. It's been going on for a month or two now, and I often ask her for clearance (if I did anything bad/if she wanted to/if I went too far etc) after nearly everything sexual. My friends have said I keep overthinking things but I keep feeling like I should be in jail. Her answer to me asking if I did anything bad is always no, but sometimes I overthink and ask to the point where she tells me to shut up about it and has even got upset at me before. We’re both 19. 

I've spoken to sexual health advisors and they've referred me to my local service, but I'm worried about something that happened recently.

I'd like to give a warning about inappropriate content before this.

We had sex this morning and she enjoyed it, but the issue and my worry is that at one point she told me to move. However, for some reason I thought I could so I kind of paused to try and do it, but about 2-3 seconds later I realised she so I did. We then switched and carried on.. 

After this I got worried about the swap, and how I tried switching with. I spoke to her and she said it was fine. She told me to stop trying to make problems out of it (not exactly what she said but along the lines of that, I don't remember exactly) and after I asked again she told me to stop because she enjoyed it. 

I don't think I had bad intentions, since after a few seconds I realised it wasn't going to work but I feel like the fact that I even tried it in the first place without saying anything or asking her could be a crime . I'm really worried that I've committed a crime and I'm a sex offender for this. Can anyone tell me if this is the case?  

I can't really bring it up again since she kept saying it was fine and to stop. On one hand I want to calm down by thinking that her wanting to switch positions meant the consent was still there, but my worried side thinks that her wanting to switch meant she technically took away consent and me staying is SA and I should be in jail. This is what I'm worried about.

She isn't upset or anything, she's sleeping next to me right now even. I do think she enjoyed it but I'm still worried even though she said it was fine. 

One advisor told me that SA also requires intentions, and I don't think I had them since I didn't intend to force anything, but what if me trying to do it without asking kind of was a form of trying to force it, and even though shortly after I realised and I did so, I don't think it clears me from any crime. I really don't know. Please help.