There are two types of mono test, a spot test that is quick but not very accurate. It frequently can be negative and still have mono. But, if it is positive then it is usually correct. Then there is an antibody test that DOES take more then a day, so it makes sense it will not be back until Monday.
We had H1N1 go through our house this winter. It DOES last more then 10 day. But, you know it when you have it. A cough is a hallmark.
So for both of these there is no treatment, beside rest and fluids.
Spookwriter, I empathize with your family. I have worked with kids and families with chronic illnesses for many years. A dozen of the years in Alaska. The closest Hematologist was a 4 hour plane flight away in Seattle. But, dealing with mild illness in folks with rare genetic disorders is different then in otherwise healthy kids. It would probably be an over reaction to take off to the children's hospital. That is in part why our healthcare system is in crisis, is because folks with mild illness do that then folks like you and your daughter have a harder time accessing services when needed.
So, Mom, if she is drinking and peeing that is good. If not, then call you Dr and get her back in. If her mental status changes, confused, lethargic, unresponsive, very agitated, then you need to do something. Take all the advice with a grain of salt and follow you gut instinct.