Postpartum fever

Hi everyone. Early this morning I woke up shivering which is the tell tale sign that a fever is on the way. Sure enough all day long my fever has ranged from 99.2-101.4 and goes down for an hour or so with Tylenol and goes right back up. I am 13 days postpartum. I called my doctor and he was no help at all and basically told me it wasn't urgent and I could wait till the office is open on Monday. ( he is a new doctor and it shows)  I am worried it might be an infection of some sort. Maybe mastitis? I was hoping he would call in an antibodic for me but instead he seemed more concerned I was interrupting his holiday . Any ideas on what's going on here ?