Sorry to say I had it for a good 4-5m (it was 20 years ago, can't remember for sure, but know it was an entire semester knocked out.)
I slept all the time and lost a lot of weight as I had no appetite at all. Had the sore throat after about 3 weeks of exhaustion.
You cannot rest enough when you've got it. Sure I made it worse by trying to carry on with my studies/social life. I also fell into a depression because I thought, "I'm just tired ffs, get up and do something" which I now see was extremely stupid. (well I was only 18)
And you must avoid alcohol - your glands cannot cope with both at the same time and you will feel 1000x worse after a glass of wine!
It does stick around in your bloodstream for ages, but iirc if you don't have a relapse within 5 years you're unlikely to get it again.
hth, and good luck!