Another "Can't"

I wanted to play the piano, even though I am pretty weak today. I just wanted to play! Well, two pieces absolutely exhausted me. It is hard to type this. And I honestly did a pretty crappy job--my left hand was behind my right hand the whole time. I guess I cannot rely on my body to be able to play when I want to, which means I should not volunteer to accompany anyone's Christmas performance. I LOVE accompanying people, much more than I enjoy solo performances. Darn.