The Grain of Rice gives it away as a tape worm segment. Very common in high flea infestation areas. You will be fine until you see your vet. They will treat the tapeworms, discuss other parasites AND really effective flea control - as that is the original problem!
good luck.
Thanks, I did treat both the dogs today for tapeworm. They are on flea regements every month. I think maybe they rolled in the lawn and got it. I have never seen a flea on either of them.