Trouble sleeping

I have been having trouble sleeping. I am not having any trouble with being tired. I can fall asleep just fine, but I am waking up regularly at about 2:00 or 3:00 in the morning. The trouble is getting back to sleep. Sifu tells is to keep the energy down or this could happen, however, I haven't noticed the energy coming up or any agitation. Also, everyone else in the house is cold when I'm hot. Again, I'm not getting hot during training, just comfortable at a lower temperature than everybody else. Is this just a coincidence, or is it related to my training?