Spontaneous 10K Night Run

So I am on a half-marathon training schedule and yesterday I was suppose to run 4 miles. But, I felt so so good that I ended up running a 10K… what. I could have kept going but it was dark outside. That was definitely the best run I’ve ever had in my life. I started out at an easy pace and didn’t really have any pace goal I wanted to make. But, my pace ended up being faster than the runs where I actually do set a pace goal. I find that it’s a lot easier to run if you aren’t worried about making a certain pace. It comes more naturally that way. The only downside to last night was that I couldn’t fall asleep for the longest time! So frustrating!  My body felt irritable and restless. Tossed and turned for 3 hours before I ended up falling asleep. Has anyone else come across this problem?