sounds like a parasite you need to see your doctor
Probably it was a parasite. Go see doctor ASAP, they'll examine the stool sample for parasite eggs, maybe take blood test to discover if you lack vitamin B12( if its fishworm). Anyway few prescription pills should correct the issue shortly.
Thx for the detaile comment, it makes me less nervous. I beleive it is a tapeworm, do u happen to kno how long it would take to rid parasites?