Based on my own experience, I made it a point to exhaust myself during daylight hours
With respect to sleep, the approach that has worked best for me is counter-intuitive, and the exact opposite of your experience. But first, a bit of background . . .
Three years ago on the advice of a sleep specialist, I restricted my hours in bed to seven per night while awaiting my overnight assessment in the sleep lab. Big mistake! Within three weeks, I had developed cardiac abnormalities so severe, I was bedridden, and wondered some days if I'd live through Christmas. The sleep specialist showed no concern, and refused to even look at the International Consensus Primer for Medical Practitioners I gave him in an attempt to educate him about my underlying illness. This disrespect initiated the first, and only, time I have ever yelled at a doctor. Needless to say, I cancelled my sleep lab appointment and didn't go back for more abuse.
Some good came out of this nightmare, however, because it introduced me to heart rate monitoring as a pacing strategy. And, I learned that for me, napping in the afternoon is essential for sleeping at night. This idea came both from the above-mentioned Primer, and a binder developed locally which provides strategies for living with ME, CFS, FM, and MCS. The theory behind the napping suggestion is that extreme exhaustion can be accompanied by an increase in adrenaline -- something that should be avoided because it makes night-time sleeping more difficult.
So, if all attempts to improve your sleep at night have failed, and you are not already napping during the day, it may be worth a try. Just make sure to end your nap by 4 p.m.
