What Causes Fast Heart Beats, Diarrhea And Vomiting?

In the past two days I've had three episodes where my heart beat increases substantially, my face, arms and chest get red and blotchy, and today, the last time, my vision was blurred, i became lethargic (Extremely) to the point where just answering someone with "yes" or "no" took the wind out of me. Breathing was difficult as well. On my way to the hospital I got cramps in my lower abdomen resulting in diarhea and vomiting upon arrival. (I had aten about 10 mins before the episode began.) They said I had a stomach flu. By the time I got there the episode had subsided, minus the stomach cramping, but some meds fixed that. I don't feel they've given the right prognosis-... They weren't listening to about what happened /before/ I came, they were only focused on what they saw when I was there. HELP! I just want answers :\