IME with mono:
Sleeping is your new BFF. I was sleeping 8-11h per night and took a 2h nap, sometimes a 3h nap each day for 4-5 weeks. That was the only way I could function.
When I was dx'd I had been showing symptoms for about 2-3 weeks, sore throat that would go away with 2d off, somewhat swollen lymph nodes, a little excess fatigue, a fever now & then that broke that night. Then one evening after a run in the rain I couldn't get warm, was running a 104F temp, achy etc. Went and got checked out. + monospot. Wasn't able to train for about 10 weeks. Started back with too much and set myself back for another 2 weeks. Think I ran a fever/had a sore throat every day for about 3+ weeks. All in all it was pretty miserable between struggling to stay awake a mere 2h after sleeping 10h at night, to the sore throat & general malaise.
You're done training for at least 4 weeks and probably in the 6-12 week range. After that you're going to need to make sure you don't bury yourself when you get back to some training. Training is your worst enemy.
Even after you start feeling normal you're going to need a lot of recovery time. (I was dx'd in early/mid Oct and it was probably June before I was truly back to 100%). 30 min a day felt like 90 for the first week or two. Even a month later a 3h aerobic ride was much more tiring than it should have been. I can remember a simple 10k/40k duathlon taking a week to recover from even though the race was ~3 mo after I got the all clear to start training again. I slept the entire 3h trip home, didn't even wake up when we stopped for gas & food, or at least they claimed we stopped for gas & food.
Bummed for you, been there know what it's like. Hope your case isn't too severe and you recovery quickly
Brian Stover USAT LII
Accelerate3 Coaching Insta