Excessive burping and flatulence

[beepbeep12]

I started experiencing this symptoms 6 months ago. I self-diagnosed myself to be lactose intolerant as I often get excessive gas and diarrhea whenever I eat/drink dairy products. Thus, I decided to start a dairy-free diet.

However, I still experience the same problem whenever I sleep in a head-on-desk position or when I'm in a really cold air-conditioned place (i.e. trains, buses, classrooms, lecture halls etc.) I noticed that the symptoms worsen during exam periods and I'm currently having my CIE AS exams right now.

I'm not sure if it is something serious but it certainly is embarrassing as I can't control it and I can even emit loud fart sounds every minute in worse case scenarios. Usually, they don't stink unless I accidentally eat something containing lactose and is about to have a long session on the toilet.

Please help me identify what exactly is the source of my problem and how to solve it or at least reduce the symptoms. It gives me anxiety especially when I'm in a crowded area (mind you, I take the train to and fro school and each ride is one-hour long).

Thank you so much!