Mono is not something I would wish upon anyone. I had it at 19 and was seriously ill. I, like slat, dropped nearly 19lbs in two weeks. COuldn't swallow any liquid and needed an IV. I was bed ridden for 3 weeks but the recovery took nearly two months. My liver enzymes were still elevated and my spleen was swollen.
I would heed the bro's advice and not train...it is a serious virus that is actualy more severe the older you get.