Try some butter before bed, just a tablespoon or so.
Also, how's your magnesium intake? And do you expose your eyes to outside light the first thing when waking? Circadian living suggests we are able to set our body's bedtime that way.
I don't get out of bed in fall/winter until it's light out, and I go to sleep the same time every night. In spring/summer, I also find it hard during spring/summer, to stay in bed once the light hits my eyes, so I have light-blocking curtains so I don't need to be up until 7 am (8 am in fall/winter). I'm also perimenopausal, which, regardless of all the above, can definitely wreak havoc on sleep.
Just dumping out my own thoughts here.