What Causes Panic Attack , Chest Pain , Dizziness And Gastroenteritis?

age 30, male: I recently went to the er with what I thought was a panic attack or a mild heart attack with abdominal pains, chest pains, dizziness, and general confusion. Turns out it was probably severe dehydation caused by what they diagnosed as gastro enteritis. They gave me antibiotics to take and i adhered to the directions and drank plenty of water. It's been a few days since they ran out and I'm not better. I have a frequent urge to go but when I do it's either what looks like spittle (mucous?) sometimes accompanied with "crumbs" and smells like a burnt match.I'm seeing a GI tomorrow but any advice I can get here is welcome. Thanks