I feel so bad for you - I can't believe that you have to wait until next week for the strep test, where I live you know the same day.
I had a few mouth sores (the worst were in the throat area) but they went away quickly when I kept rinsing my mouth with salt water. I kept salt water in my bathroom and kitchen and rinsed my mouth out everytime I went into either room. This is what the chemo nurses had instructed me to do.
My oncologist gave me magic mouth wash for pain, if this isn't what you were given - perhaps you can request a prescription for it - here is some info:
http://en.wikipedia.org/wiki/Magic_mouthwash