Relax. Try deep breathing to where my stomach fills and raises up. Slow, deep then Repeat. Don't fret. *** It *** happens. Go to a "happy" place? Beach. Walks. I like recalling the awesome sun shine while floating in the pool in the summer. It is my happy place.
Just lay there and know even THAT is somewhat helpful. If it is something that is worrying you, why wait until bed to deal? Write down the problem and add: Things to Do Tomorrow. Works for me.
Truly understand that sleep is necessary for most of your body's immune functions.
Look into BlueLights and how to avoid them after sunset. (After that, your natural release of melatonin will come in handy at bedtime).