I am also worried because we kissed and because i sometimes have hemorrhoids. So possibly any virus could have came in from small bleeds on my anus.
So, this is something in which you need to understand how anxiety is impacting you. You had oral sex which is not 'no' risk but low risk. You aren't talking about anything related to an std when you say you had stomach pains/abdominal pains the night of, after, etc. receiving oral sex. That's nothing at all to do with oral sex. Perhaps constipation or GI aftermath of being so drunk. If you don't have any std symptoms (sores, discharge, etc.) then there is no reason to worry or test. And kissing? And you have hemorrhoids. These are unnecessary facts.
I know when someone cheats on their spouse, it makes them feel super guilty and sparks anxiety that they gave their significant other something I personally think we must protect our loved ones. This means either not having sex or sexual activity outside the relationship or using a condom. Maybe not drinking so much. This is not to shame you but to just suggest some clean up of things in your life that work against you.
But for this situation, I would not be worried about the stomach pain and unless something happens to suggest so that you got an std.