question: my 15yrold grandson  has become  extremely thin over the past few months. he has become lethargic aand complains about not feeling well. He has had a fever and cough on and off and staggered and fell in a store.  At that point he was diagnosed with mono .Bloodwork showed he had been exposed to mono.  He still looks pale and tire easily.  He is also still very thin. Does he have active mono or is this maybe something else after all these months?