One Morning Last Week I Woke Up And My Stomach

One morning last week I woke up and my stomach was slightly bigger like I had gained weight, a stomach pouch. I do not have a scale but my belly is bigger for sure. Hasn't seemed to gotten any bigger or smaller since I first noticed. I am in college and walk everywhere and am in the marching band, so I am not a couch potato, but I do not get too much exercise beyond that. I also don't eat the healthiest but I don't eat much in a day either so I know I do not go over the recommended calorie intake for someone like me. I am a female, 21, about 5.6 and around 130lbs last I checked. Almost two weeks ago, Wednesday October 29th, I was making out with some guy that night and he fingered me for a few minutes but we did not have sex. It was the first time I did anything of that sort so not sure if that pushed something either. I am not sure what caused the sudden change.