Please help - ROCD after night of drinking

has anyone experienced this or have any advice on what to do. okay so my senior prom is today and i’m in a long distance relationship so im going alone with friends and there’s an after party at someone’s house and it’s just your basic high school party with drinking and everything and ive never been to one but i wanna go with my female friends (im also a girl btw) but i have an rocd fear of cheating or something if i go. ive only ever gotten drunk once and all i was thinking abt was my boyfriend so i don’t understand the cheating “because you were drunk” thing. if i go to this party i do wanna drink a little but im just scared cause im overthinking that something will happen even though i would never do that. i haven’t asked my boyfriend about it yet as he’s at work but i am just not sure what to do.

I have this deep fear I’ll accidentally cheat on my long term partner. This fear was initially triggered a couple years ago after being at a bar with my friends where I enjoyed the attention of being flirted with by a stranger. Because of my enjoyment of receiving verbal attention, I began spiraling about what if I accidentally cheat. Since then I have made multiple confessions to my partner to seek reassurance, replayed events over and over in my head, spent hours googling/looking at reddit threads, and now I dread “bar like” situations where I know my partner won’t be around. Today I was triggered and have wasted about 4-5 hours of my day ruminating. Does anyone else with relationship ocd struggle with this fear and have any tips?

For context, I was previously diagnosed with GAD and OCD. Months ago, after a night of drinking with coworkers I experienced slight hangxiety, but I remembered most of the night. At work when I asked a coworker if I did anything weird he made a joke that really wasn’t funny. This joke caused me to doubt my memory. I think I had thought I was more sober than everyone else when in reality I was not. I remember checking on a coworker who was slumped over in the drivers seat of his car and in no state to drive and asking “you good?” The next thing I remember is that I was in the drivers seat of his car reversing out and I think I assumed that he and our other coworker were also in the car. Our other coworker stopped me and told me to pull back into the parking stall and come back inside. I remember the events both leading up to and after that all the way until I got home. However the small gap in my memory had been causing me a lot of distress, so I asked that coworker who I went to check on who was the only person that was present during the gap in my memory if I touched anyone or let anyone touch me, to which he said no definitely not. He also said that he wasn’t in the car when I was reversing out and that he vividly remembers that I was the only person in the car. When I explained to him that the joke that our other coworker said made me worry that I might’ve done something that constitutes cheating on my bf he said no that guy is just weird and says effed up stuff. I feel a lot better, because he has no reason to lie and he doesn’t seem like that type of person. However I still feel unsettled, so I plan to call my doctor’s office when they open in the next hour. I’m wondering if anyone has experienced anything similar/has any advice.