Stomach issues

I got to school I'm a sophomore in highschool I had my gallbladder taken out last year when I was 14 I'm now 16. So at school right after I eat lunch my stomach starts cramping all the way into my chest, my mom says its gas to then I took a gas x that I had in my purse and it didn't help at all. I was wondering if you all had any suggestions on how I could maybe help it.