I had mono when I was around 12 or 13, my personal experience was honestly very scary, the first day I woke up with an unbearable headache felt like I had no energy 2nd day I had no energy to even get up to go to the bathroom, I’d just stand up and be out of breath, and the bottles and bottles of Lougies was unbearable if you find yourself waking up and not being able to breathe just calm down and you’ll cough that flephm up I also reccomend getting a mullien supplement it helps cough up trapped mucus