My 18 yr old son home from college for the holidays developed a fever and possible flu for 2 days, felt better for 4 days, then developed a painful sore throat, painful swollen lymph node and a rash. He was diagnosed 3 days later with strep throat and prescribed penicillin. This was 7 days ago. He feels better but has lost his appetite and is tired all the time. Could he have mononucleosis or a side effect from strep throat? He is supposed to go back to college out of tow tomorrow. What do you recommend?