Yes mono does tend to get worse before it gets better when you're starting to recover from mono.
For 1 to 2 weeks you'll usually have a high fever and severe sore throat but occasionally the sore throat and sometimes the fever can last up to 4 weeks.
Fatigue from the mono can last a little longer.
When you have mono you're usually contagious for up to three months once the symptoms of mono has subsided.
But in some cases of mono the person can still be contagious for as long as 18 months.
Once the symptoms of mono appear the symptoms of mono can last up to 4 weeks and then you're contagious for at least 3 months after that period.