I have no idea how sick vocalists make it on stage. I am still recovering from t

I have no idea how sick vocalists make it on stage. I am still recovering from the flu I had last week. And I know that my lungs, diaphram, vocal cords, and maybe my whole body, are not in the same shape as a professional, but I just tried two songs and pretty much failed atrociously. Staying on key is not a problem. But it just sounds flat and strained. Empty.

I got nuthin’.