I like this little scale from Eric Cressey:
Scenario 1: The Health Scare
A sick athlete who can't decide whether or not to train.
This was actually a system I stumbled upon by accident. An athlete emailed me saying that he woke up feeling pretty crummy, and wanted to know if I thought he should come in later that day. My response was as follows:
"On a scale of 0-10, how bad do you feel? If it's a 10, you should be emailing me from the hospital. Consider this, and then scroll down to the bottom of this email..."
Blink 182 Nurse
I then hit the "return" key about 30 times, and typed the following:
"If it's 0-3, you're fine.
If it's 4-5, go in, warm-up, and then see how you feel.
If it's 6, just go in and do something, even if it's just a warm-up.
If it's 7, push things back a day.
If it's 8-9, take a few days to rest.
If it's 10, you shouldn't feel good enough to check emails."
Of course, it turns out that he had Ebola and died, so he was really an 11 or 12. It's tough to check email when your eyes are bleeding.
If it's so bad you couldn't sleep I would recommend taking at least a day or 2 off.
I've found that honey can help sore throats, either in tea or if it's really bad a straight tablespoon.