My first guess is you're taking in too much pepper. I take a smidge from a capsule and put it on my tongue and take a swig. You do not need an entire capsule in one go -- that is way too much pepper. Think of it this way, would you empty an entire capsule and put it in your drink. I wouldn't! A capsule can last you 2 days :)
I took a capsule once and burped pepper for a day, which burned my throat, as well as burned my bum coming out. OUCH!
Try to cut back on the pepper (remember - a pinch is not that much).
Also - the symptoms you're feeling is detox...pure and simple. The first reaction is to eat something, but try to avoid that. Drink loads of water and 6-12 lemonaids a day (with a little pepper) and you'll feel great!