See a Doc, sonic, soon... fatigue can manifest in a variety of ways, one of which is to present with flu-like symptoms, but can follow that with some serious problems. I don't know your health/medical history, (and don't care to) but I'm willing to bet that even if it is an actual "bug" or illness you are stressed from all the riding, booze, fun, lack of sleep, and etc. to the point your body isn't going to easily fight off even the tamest of attack. This is advice/idea for any one who attended. Long rides, different environment, altitudes, new flora, lack of or excessive amounts of normal things, turning doorhandles that have never been cleaned, rest stop bathrooms, etc... All you superheroes need to recharge, you aren't spring chickens any more!!
How many of you changed the oil, mounted fresh tires, drained fluids, lubed parts, washed and detailed the bike when you got/get back? Now do the same routine with your most vital component... get some sleep and take yer vittaminnz!
Get well, sonic and all of you!
C