I experienced something very similar, and tried many things including looking at what I was eating. Nothing worked, except I did have some limited success when I followed the principles put forward by Michael Mosley in his "Fast Diet" in that the two fast days, I slept like a log and work up 'bright eyed and bushy tailed'. On the non fast days, I again had problems going to sleep and as a result woke up like a zombie.

BUT I have been able to change that round. And surprisingly, to me at least, it was when I committed to not being exposed to any digital media (no laptop, no tablet, no tv, etc) and hour before going to bed.

Instead of just going to bed and shutting my eyes and hoping to switch off, I have changed my habit in that I now always make sure that last thing I do before switching off the light, is reading a few pages from a good old fashioned book. Some nights I manage a chapter, other nights just a few pages. Important is that it is not business related, and that it is easy reading. Of course thoughts still come and go, but I do not give them unnecessary attention, instead I let them come and go, and make sure that the focus is on reading further, rather than pausing to think about what thought has just come up.