I hven't personally have that happen but I can understand why it would - it's like taking off a scab too soon, the skin bleeds.
It could be that you need to give your colon a break from fiber and instead start your cleansing with a series of colonics. Beware of taking any of the pharmecueticals the doctor gives you, check them online and with a PDR first. Most of the ones they give you will jsut make you worse. Al you really need is some drinkable aloe vera juice and a better diet! :)