There are a whole lot of other factors which can contribute to sleep or lack there of. I have just recently found that my bladder has not completely come back into operation since surgery in May. I am up and down at night, and as a lot of you will know, its going to sleep which is a real issue as you can't shut your head down.
I know my head is like someone is holding down the channel changer on a remote control for the tv. Image after image.
Also take into account the day before. Yesterday I had it out with the 18 year old. I was ready to knock her teeth out. I got what I needed to say out in the end, but it left me all fired up and hence I could not relax for sleep that night. You also have to factor in all the other stressors both good and bad that fill your cup up. For instance, if there is a jerk at work who has been giving you grief, you will spend your night thinking of ways to finish him (jokes).
I thought that once I had dealt with a lot of my traumas, the horrors that kept me awake, that I would sleep like a baby. Well, that just isn't quite right. I occasionally will read a story or see something that reminds me and they come back, but I think we are wired all different now and then you also have to take into account military conditioning. You were trained to sleep with one eye open. After all this time, the kids and other people don't understand. My therapist told me once that it really needs someone to constantly tell you every time you wake that its ok. You don't have to be on alert.
Just rambling.