2. Tiredness
As we will see throughout this list, the precise symptoms of mono can vary significantly, with some people experiencing only a selection of those listed here. Teens and younger adults will tend to experience entirely different collections of symptoms as compared with older patients.
Teenagers in particular are among those most likely to suffer from extreme tiredness and lethargy. This can make it difficult for them to go about their usual activities and they may struggle with mundane tasks or simply find that they get worn out very quickly.
This is a very common symptom of any kind of infection, as the body expends energy in combating the infection. However, this is a far more noticeable and extreme symptom in the case of mono.
This extreme tiredness can also last for a very long time. It may last weeks or even months after the other symptoms have all cleared up.