Hello, I am a 15 year old girl who is 114 pounds and 5 feet 5 inches. For the last two days I have been having diarrhea with nausea, and I just found a light grey worm in my feces. What can this be? Also, I lost about 3 pounds in the last week, but I have been eating more than I normally do (I'd say about 3,000 calories a day-I have a fast metabolism) and I've even been eating ice cream, cake, etc.