If you are laying in bed for 45 minutes before falling asleep, you are not sleepy enough when you get in bed. The brain trauma sleep specialist I heard said you should be able to fall asleep in less than 10 minutes, 15 at the most. She said if you are still awake at 30 minutes or so, get up and get sleepy again. If you start to get fidgety, get up and find something to distract yourself while you get sleepy again.

The sensation of a bladder than needs emptying limits how sleepy one can become, especially with the sensory struggles PCS patients have. Consuming liquids should stop hours before bed time except for sips for medication and to wet the mouth. Unless I am very sleep such that I stumble into the dark bathroom, I can rarely go just before getting into bed.

btw, By the time I head to bed, all of the lights are off except for maybe a stove light or my wife's underbed nightlight that reflects on the floor. No light that strikes the eyes. I can walk to either bathrooms in the dark and find the seat. No need to aim when you sit. I've usually been watching Netflix on my computer with the screen on low light and the headphone volume down low.

There is a difference between physical tiredness and sleepiness. Sleepiness is neurological Tiredness is physical. Sleepiness helps you go to sleep.

Your can disrupt tiredness with physical activity. Sleepiness needs waking activity/mental stimulation.

If I get in bed and lie there for a while and start to fidget of my eyelids start blinking, i know to get up and start over.

It has been a lot of work for me to learn to get to sleep, much less learn to sleep on my back.