Dead arms

I thought I lost the use of my arms. I have never felt so bad after a workout in my life, and the workout was two days before it hit me. Apperently I overdid my first group personal training class so much that my muscles quit on me. I knew I was reaching my limit when I was doing it, but being the competitor that I am I didn't want to stop in the middle of a set. I guess I should have. I won't make that mistake again.