Adele...Let me first state that I am not a physician, and I certainly can't pretend to give you medical advise. My first thought was 'the antibiotics has caused a yeast infection (thrush) in your mouth'.....Hopefully, the white patches are nothing more than that.
Please don't panic...Monday will be here before you know it, and then you'll have some facts to work with.
Hang in there...all of us will be here for you, no matter what the outcome.

Lois & Buzz in NC