Corinna ... Forgetting the words is the "nature of the beast." I cannot begin to tell you the number of times I've had to make up words as I went along. My particular idiosynchrasy is that on occasion it has caused a mental, e.g., in the mid 60's I was singing in a club in Cocoa Beach, Florida, and forget the words to "The Times They are A'Changin'" I know every word when I'm singing along to a tape in my car, but have never, since, been able to perform it for fear the same thing would happen. So ... you are probably better at it than you think.