I've been sick all week and hardly getting any better what can i do?

Please do not go to the function. You would not be welcome. If you still feel bad after 14 days see a doctor (you may have strep or possibly Epstein bar, a contagious and serious illness). Epstein bar can be fatal, and is very common. It can be passed on by bodily fluids, including kissing. Take it easy. Avoid straining (do not lift anything heavy - nothing over 10 pounds, and no heavy exercise. If you had E-B you might rupture your spleen). See an M.D., ASAP.