Ack, I know how much that sucks! I was diagnosed with strep & mono 1.5 years ago and I'm not sure how much of the symptoms were from strep, and which ones were from mono, but I know that I did not exercise for those 2-4 weeks that I was sick. I was also put on antibiotics (azithromycin) and steroids, I'm pretty sure. I know that just a day after taking the medicine, I could already tell I was feeling better. If your 5k is on Saturday (7 days from now) you may feel pretty ok by then, actually. 6 days of antibiotics should work pretty well...just listen to your body. Don't run it if you're still sick and not feeling that great! Maybe a slow jog or even a walk, if you really want to run it. Make sure to stay hydrated! Good luck & hope you get well soon!