It may have been that. I tend to feel that way after intense cardio, and intense is a subjective deal.

How well were you feuled up for your workout? I know you are trying to lose, but making sure you are nourished properly is important. I like to get some carbs in there no more then 2-3 hrs prior, and as well have maybe a banana closer to, like say 1 hr or less. It sounds like you needed some sugars in ya. A simple banana will help with that.