When my baby was younger, every time she was crying or winging or hyperactive I thought that it was her levels going herr crazy. However everytime , the levels were in normal range. She gets never angry, but she sure has a character, and this is all day long, no matter what her levels are. Sometimes when she is sick, she is under the weather. I never check her blood levels with a fever, but I think that phe has nothing to do with it. Is is a normal child with mood variations.