Hmm. Well, there are pin worms and tapeworms....with pin worms you would also have anal itching, mostly at night. If you don't, it's probably not that. Now, tapeworms are not very common but yes, you can get one, and it would leave the small specks in your stool that you're seeing, and would also cause you to have constant hunger. But like I said, that's not very common and the circumstances surrounding contracting one would be things such as - visiting another country and eating undercooked pork or even their fruit; if you have a pet, there's a chance the pet could have one which could be transferred to you. But there again, even if you had a dog with one, there would have to be something on the dog that got on your hand when you pet it, then transferred to your mouth via eating if you didn't wash your hands first. Have you recently gotten a puppy? Have you done any traveling outside of the country? If you answer no to these and honestly do not have anal itching, I would have to agree with your doctor.