My stomach makes grumbling, farting, unusual sounds when i get anxious/ can u help me stop it?

It's humiliating. When i get nervous, which is a daily basis, it groans. when i think about it, it happens. and not thinking about it isn't as easy as it seems. and i know it'll get worse once school starts. what can i do??? any breathing techniques? i tried drinking TONS of water and not eating but it stilll grumbles.