Dear Sleepless in Slovenia,
Wind down an hour each night before bed. Meditate. Listen to relaxing music. Gently stretch. Refrain from screens or exercise!
As you fall asleep, take your mind off your troubles. Focus on something simple.
A favorite practice of mine is to imagine a rampage through downtown and to count each person stomped until I reach 100. When I lose track of the count, I start the rampage over and stomp again.