I would try to repeat the same ride and see what kind of results you get. Sometimes, if you are overtraining, you'll notice a drop in your heart rate while riding, then over time, you'll notice your heart rate will be pretty high when doing what you would normally consider a pretty easy workout. Pay attention to your resting heart rate too over the next few days. If you find that you're more than 10 beats higher than normal, take time off. If it's just a few beats higher, I would still take it a little easy for the next few days until your resting heart rate is back to normal.