Is my OCD causing me to feel the urge to admit something?

Yes, I have experienced this too. It is a compulsion called confessing. It’s where you have this intense need to tell someone something that you did or said. For me it happens usually when whatever it was that I did or said is making me feel bad about myself. Then for me, I want to feel better about myself & my ocd says confessing it to someone will make me feel better. For me it also goes right along with another compulsion, that is reassurance seeking from others. Try to sit with how you are feeling. Allow the distress to be there without doing a compulsion. The anxiety you feel will rise the longer you sit with it, but eventually it will come down on it’s own. You can do it. Your brain will say that you can’t handle feeling the distress you are feeling, but you can. It just takes lots of practice. And lots of having compassion for yourself while you do this.

Yep, all the time, allthough lately it doesn't feel like an urge, just something I wanted to do, withouth much anxiety

Yes I have as well. Since you have soocd under one of your tags and is what I struggle with that mainly its what I can relate to. For me it made me almost come out to my family and it felt that I really wanted to. The thought came into my head again It was scary but I had to ignore it. Funnily enough I imagined a whole scenario in which I did come out to my family and ended my relationship due it . I laughed at it. But yes all in all, it is one of the things of ocd.