Hello, i had mono when i was in my early 20s, a very bad case of it. The thing with mono is you have to rest and sleep and not do anything exertional. It seems that you haven't rested enough, also when i had it, the symptoms lasted for about a month. It was horrible, just like you said i had the bad sore throat, the fatigue was unreal and the swollen glands and the achiness. The best thing you can do is just rest as much as you can. As far as a relapse, it is possible but i dont think you ever got rid of it. In fact, once you have Mono, you never get rid of it, the T cells are always present but the symptoms are gone. It took me years to feel like myself again and I never really felt the same after it, I used to be able to stay up all night i had gotten it when i was 24, after i had mono my energy tolerance went way down to where i would have to be in bed by 10pm because i was just so fatigued. One of the things i was told to take was lots of vitamin and C and Echinacia, although I was allergic to the Echinacia i didn't take that. Just try to rest and not do to much. You will get better. HOpe this helps!