Seems obvious, but don't overlook caffeine. Even a little messes me up now, despite drinking it all my life.. If I have more than 3 cups, or any after 12pm, I have problems - restless sleep, have to get up multiple times at night, etc. And of course what does one do after a poor night's sleep? Drink more coffee of course.. so it becomes a vicious cycle.
I should probably quit altogether, but as with drinking I'll probably ride it as long as I can, lol. Once an addict always an addict. I'm tapering back, and it's already made a big difference. Hopefully I can get down to two cups per day.