I am CPR certified but did not act. Is that Negligence?

I was working at my store and my managers were crowded around a man laying down purple to the face. It was my first time ever seeing an unconscious person who wasn't breathing (he was a big man). I saw him lying there and I went blank, I don't know if I went into shock or what, but I could not move and I wanted to cry. One of the managers asked any of us if we knew CPR. I did not answer and I couldn't. People were already calling 911. I'm certified but I did not have my card on me. I was scared, shocked, and completely depressed that if I were to perform CPR I wouldn't have done it correctly or effectively. Instead I managed to spit out "30 compressions and 2 breaths" and he started doing it (he was not certified). But as my manager was doing compressions color started coming back to the mans face. I know what I did was wrong, I should have acted, I could have probably helped the man, I feel so guilty. I don't know how he's doing. Please, I need some advice, reurance, or the answer to my question.