Try some digestive enzyme pills. I was getting lots of gas and frequent washroom trips. Few days into the pills, things have improved - not 100%, but much improved. In my case, I think it was the high protein.
The digestive enzyme pills that I bought are for protein, carbs, and fiber if I recall correctly.
High protein doesnt cause gas. It's either lactose intolerance or the SHIT LOAD of FILLERS they put into whey protein tubs.