I've struggled with the same issue since the birth of my daughter nearly 5 years ago. It has come and gone and some weeks are worse than others. It was starting to cause me anxiety because bedtime had become the enemy. Just the thought of trying to go to sleep caused anxiety which made it worse, and thus the vicious cycle. I struggle with a low but manageable level of anxiety anyway, but it's enough to keep me up at night just like what you mentioned, and my brain won't turn off.
I started taking Benedryl (Wal Mart brand - the active ingredient is Diphenhydramine) at night to help me sleep and it worked. I don't take it every night now, but only when I feel like I need it. Not the best, but it's what has worked for me and it's better than some of the alternatives (as far as over the counter or prescription meds go at least). I've tried milk & honey at night, calcium/magesium (Natural Calm), different teas, setting a routine, a warm bath, sooo many things and nothing significantly helps except the Benedryl.
I have a friend who suggests taking melatonin and she takes some kind of mixture of things that came in a box (like a "kit") from the health food store. She says it helps sometimes. I have not checked into those things yet due to cost. We're a family of 7 on one income and all natural supplements from the health food store can get very costly.
I hope you find something that works for you. Insomnia stinks!!! I'm interested in reading other's comments.