Stomach discomfort after getting my gainer

Hi guys,

I used to drink mess tech gainer after my workout and from yesterday I changed it to another brand.

I ate 5 gr creatine before workout and new gainer after workout. Today I am feeling totally full and I can not eat well and also feel pressure in my troth.

I am lactose intolerance as well, I wanna know if creatine caused it or my body is allergic to the new gainer?

What is the solution and what this stomach pain comes from?

regards