I have had this problem for years, and I have found only a few things that help me.

Although it is not recommended, many years ago I began playing a small handheld electronic Yahtzee game while trying to fall asleep. It has since progressed to games on my smart phone. I turn the brightness down as low as possible, to still see what I'm doing. I am always able to drift off with the device in my hand, but without ruminating!

The other things that have worked for me personally are diphenhydramine (Benadryl) and recently, melatonin. These make the game-play to falling asleep time much quicker.

You should of course make sure your doctor approves them, but these things have been a lifesaver for me. Now I just need to work on random daytime rumination, which also is helped with game-play, but that's not always possible!

Best of luck to you! ☺