fever

Nathan has been sick since Thursday, here's the thing though, his only symptom is a fever, and it comes and goes. He does have a cough, but he had that before the fever started on Thursday. He was fever free all day Saturday and Sunday morning, and then in the afternoon he started looking blah again and his fever was back. So he stayed home today, and I was planning on calling the doctor, but he's been fever free again all day, so I didn't. Does that make me a bad mom? He's been jumping around and playing all day and acting just fine other than his cough, but he's the kid that will have a cough all winter long whether he's really sick or not. It seems like once something gets in there and irritates his lungs it just won't go away.
So now the question becomes, do I send him to school tomorrow, or give it one more day just to make sure he's really over whatever this is?