I have noticed a strange phenomenom.
I exercise virtually everyday, either cardio or weight training.
On the night after I perform cardio(which I do in the morning) I tend to sleep much deeper and wake up more refreshed than after my weight training days.
What is going on? Hormones?
Now you went and did it. Lured me outta my cave where I was nice and cumfy. You have hit on a subject that ties directly into a point of interest of mine, as of late. Thanks to TT. 
Anyway to keep it VERY simple. Brain Chemistry my friend. That is what is at the source of your problems.
Weight training induces a rise in the production of dopeamine levels in your gray matter. This gives you energy, keeps you awake, kinda like taking a stimulant. Try doing your w/o early in the day if you can. Should help and get you fired up for the whole day.
Steady moderate Cardio on the other hand raises seratonin levels. Relaxing you. Making your sleepy and leading to a good nights rest. Try and hit the cardio a few hr before bed if having trouble sleeping.
Once again this is a very siple dumbed down version of what is going on. If you want to go into greater detail I suggest the book that was suggested to me. “Edge Effect” by Eric Braverman. It is worth even thumbing through at the book store.
Hope that helps
Phill