I take doxylamine succinate 5-10 mg about an hour before bed and find that it helps with sleep much more than melatonin, which only seemed to help with a very time-limited form of tiredness (it wore off and I'd wake up).
Still, even the antihistamine (sold as a sleep aid) can't do all the work when something big is going down the next day. Like a meeting with a big client requiring a lot of travel. A big stressor must be addressed.
In that case though, I find that writing 1000 to 2000 words about everything that could possibly go wrong gets me to the point where I can sleep like a baby. Precisely because I'm attaking the source of the anxiety. Most nights though it's easier just to do some basic organization and scheduling and take 1/3 of a little pill.
In the morning I do often take 50-100mg Jet Alert to blunt the fade-in. It's way easier to feel comfortable taking caffeine when fully rested.
An experiment in progress always, but at 9h average sleep (excluding waking times as recorded on FitBit) I managed to go 10 months between illness, as someone with an autoimmune condition (sjogrens). My previous record was 4 months. On top of that, no more depression. My subjective day ratings have gone through the roof. I have to laugh when I'm working with 10 hours of sleep and literally cannot find a single thing to be sour about in my entire life condition (the journaling template I use takes me through this). Plenty of problems, just more resources to work with. Sleep is worth the chase.
Edit: While I'm talking about anxiety, I have been testing L-theanine recently and so far it seems to lower the anxiety floor a little bit. There's nothing like getting your stressors sorted directly, but sometimes things are more complex than that, and if supplements can help, great.