23, female, taking Wellbutrin and TriNessa

I am having difficulty staying hydrated. When I try to drink any substantial amount of water, I feel sick and get diarrhea within 30 minutes. It doesn’t matter if I’ve recently eaten or not, and filtered vs. tap water doesn’t make a difference either. This has been going on for at least six months, off and on. More recently, within the last month, I’ve been having some chest pain on the left side that feels like heart burn, and some palpitations. My GP said my heart is fine, so I think it’s because I’m always dehydrated. What can I do to keep from getting sick off water?