I lost parts of my voice and I have a horrible cough. Help?

I had a sore throat before going to a concert. It was nothing major. I did not have a cough and it felt like I had just been talking to much. I was getting ready for a speech i had Wednesday so i was talking a lot three days before. Wednesday night was the concert and while having a good time and singing along I really messed up my throat. On the ride home while singing along with friends I noticed my voice was getting worst and worst. By the time i got home my "false setta" or what ever you call it was completly gone. I found this weird because no matter how sore my throat has been in the passed, it never messed up my "false setta." Tommorow makes a week and it still has not returned. I went to the doctor and was tested for "staph" and "mono" but both came back negitive. Could I have permentantly damaged my voice?