Symbol is un-converting?

While I'm inside a symbol, I have a continuous frame, and I created a key frame around the middle of it, and after the key frame the symbol status disappears. As in, Before the key frame, the ball I'm animating is a symbol, but afterward, it is not. The ball is still there, it just isn't a symbol. I can't put the symbol back into the animation, because I am inside of the symbol already. Thanks a trillion