Sounds like you have some lactose intolerance going on; get some Lactaid pills at the grocery or drug store and/or Lactaid milk (or other, similar brand; I use it in my coffee instead of regular creamer). It really made a difference for me! http://www.lactaid.com/ I carry the little packets around in my wallet and if I'm at a restaurant and eating a lot of cheese (pizza?) in a day, omelet for breakfast, cheesy dinner, diary dessert, etc. I take one of those with my first bite. I didn't know there's a lot of lactose in caramel and had a horrible Easter a couple years ago when I got a caramel-filled milk chocolate (milk chocolate also has lactose) rabbit as a present! I didn't discover I had a problem though until I tried to eat "healthy", oatmeal every day but discovered I couldn't drink consecutive glasses of milk (milk in the oatmeal multiple days in a row and I was in bad pain after the second day).

I have problems with coffee (and beer!) also and chocolate. There's lots of those miscellaneous side-foods that have chemicals that can mess you up if you're susceptible and it has gotten worse as I've gotten older. I'm getting annoyed at how much I sneeze (but paying some attention: coffee, beer, chocolate, mints, wine, etc.).

I think the diarrhea before your period could be "normal" too, sometimes. Here's a good list of lovely PMS-possible problems:

http://teenshealth.org/teen/sexual_h..._problems.html