What's wrong with my stomach? It's always upset.?

My Mom has Celiac disease and she uses different flour for baking sometimes, but every time I eat it I go through two to three hours of painful vomiting a few hours after I eat it. Once all the food comes out I start to vomit orange-yellow phlegm-like stuff. It's awful and I don't know why it happens, all I know is that I can't eat my mom's flour. Also whenever I eat my stomach gets upset for no reason, it just feels kind of sick. At first I thought I might be allergic to something but it happens with almost everything I eat. Are these two things related or completely different? Help me please.