Lose/reduce a cold in three days?

Alright, I am aware that there is no cure for the common cold, but I've been asked to sing the national anthem at a home football game this Thursday. It's a really big deal for me, and I really don't want to tell my principal I can't do it because I'm sick. My cold isn't too bad, I'm just congested and coughing. Any ideas/methods/ways y'all have used to get rid of your cold quick? Thanks so much! :)