Eat lots of honey with crushed aspirin in it. My Granny had that when she was dying of cancer. Sweet chilli sauce will also burn the germs away, and try to eat bread with a little salt. Drink fanta orange, it's full of Vitamin C, and Creme Soda by Sparletta has lime-juice in it, which helps a lot to prevent immonodeficiency-related illnesses.
Why is your system so run down? Too much exam-stress?