Hi I Am About To Be A Lead In A

Hi I am about to be a lead in a musical this weekend for three days in a row and I have a very sore throat and fatigue. What are the best over the counter perscriptions that I should take in order to be vocally healthy by this Friday? By the way, it hurts to talk and swallow. It hurts all the time since two days ago. I just went to a nurse practitioner and they said it wasn't strep. I also have a mild cough.