water weight? maybe you weren't hydrated at all before your cleanse started? i think one gallon of water is supposed to weigh 8 pounds, so if you were dehydrated before your cleanse you might just be holding onto the water you've been drinking.

are you doing salt water flushes or taking an herbal laxative tea?

if you're female are you nearing the start of your period? that could also be the culprit. don't let it bother you too much, i'm sure the weight will start to come off! good luck!