I was having the same problem only a few weeks ago. Here is what I did. I saw this on Dr. OZ, try drinking some valerian tea before you go to bed. I use the Celestial Sleepytime Extra, caffeine free with an herbal supplement, or I drink the Celestial Chamolile herbal tea (caffeine free) with 1 dropper of melatonin 3.5mg. I got the melatonin at a health food store. i only had to do this maybe one or two nights and now I can go to sleep and sleep all night. I don't have to use it each night.
Another trick is one my sister told me to do. It's just a little prayer: My dear sweet gentle Jesus, I pray you give me the strength I need to get though this. It works for me. Good luck.