I had a similar problem. It didn't matter what time I went to sleep, after one and a half hours I'd wake up and not be able to go back to sleep until my alarm was going off. I couldn't take regular sleep medications due to the antidepressant I am on. My psychiatrist prescribed gabapentin. It takes right at three hours to kick in so I usually take it about 7 pm. If I take it on a full stomach it isn't as effective. If I take it on an empty stomach it kicks my butt when I hit that three hour mark. If I get up and am moving around a lot it counteracts and postpones the effect. If I'm watching TV or reading it takes effect at the three hour mark and I have to lie down. I've been taking it for years now. It also helps with my arthritis pain when I'm trying to go to sleep and while I'm sleeping.