Stomach issues and exercise

Hi All,

I'm back after a considerable break from my tri exercising. I started spinning classes ~3xs per week for the last month and have recently started adding running into my training. Unforunately, in the past week, I have been plagued with a lot of stomach issues, including indigestion, gas pains, burning in my stomach, high resting heart rate, sweats, etc. I let myself rest up for a few days (especially because I have been unable to eat or drink much), and saw the doctor. I was prescribed rinitidine and a proton pump inhibitor (both stomach acid reducers) and have started taking gas-x (lovely, I know). After another day off and some rehydration I started exercising again, but have found my stomach problems are causing me great distress when exercising -- so much so that I have had to cut my exercise short (especially when my HR monitor says my HR is way too high even at light to moderate exercise).

I know this is a tricky question, but I figured someone might have a good solution. Any ideas on how I can reduce the stomach pain and belching, so I can just get on with my exercise??

ANYTHING would be greatly appreciated!

~Kristin