Food Allergies Treatment

About a year ago, I noticed that I was having trouble digesting cream cheese and icecream. Then it got worse, and I counldn’t digest milk, butter, whip cream…etc.. I started doing research and came up with Lactose Intolerance. So I avoid dairy and take a pill. The problem is, I’m not sure if its Milk/Casein allergy or lactose intolerant. Its so bad that I cant eat breaded food, cant use certain hair products (casein I think) and I cant even take tums, or pepcid because they contain lactose, even if I take a my lactose therapy pill.
Does anyone have a casein or milk allergy? I want to know some signs and sympoms and what to look out for that may let me know which one I have. (Yes, Ive looked online but I want REAL person experiences)