Chills + goosebumps = trouble!
Sounds like a heat illness to me. I wouldn't be surprised if you feel sluggish for the next few days. Almost like you are coming down with something. If you do, then BINGO! It was the heat, not your lack of motivation.
It's heating up here in the southwest, so it's time to really watch our hydration. Not just DURING the training, but before and after as well. Also make sure you are taking in enough sodium.
Be careful out there!
Denise