Mono is an autoimmune condition that can attack your liver and that's why it is similar to MS and Lupus, both of which are autoimmune diseases, but attack different areas of the body. Not to scare the original poster, but another common by product of mono is rheumatic fever, which can permanently damage the joints in your body. I think this is something that happened more in the past before the higher level of medical care we have now. Back when people had poor nutrition or poor recuperation conditions.
Mono is nothing to mess with at all and it's not just "another" childhood ailment. It's something you need to be very careful with for years to come. I blame mono on my ability to sleep 12 to 14 hours at a time without waking and its been 30 years since I had it. I still need a great deal more sleep than most people I know.
And I totally remember not even being able to swallow my own spit too!