I have a 10 yr old boy, normally very very healthy. He and a friend went fishing in the creek and now he is sick. sore throat, headache, stuffy nose, stomach ache, stiff neck fever 101-103. Went to urgent care said dont know what is wrong. did a strep test came back normal, checked for mono came back normal. he has been sick like this since monday and not getting any better. Have given him tylenol for headache and fever.