I had mono when i was younger and sometimes i feel like a low grade mono type thing comes back when i get a virus anything i can do?

Rest and recuperate: The varied symptoms attributed to "mono" are common to a variety of viral illnesses. Thankfully, your progression into adulthood has validated a good basic immune system with your good basic health so far. When sick; sleep well, take breaks, eat a balanced nutrition and reduce exertion as needed. I know of no worthy supplements that make a difference in recovery.