I had dreadful insomnia the first time I stopped drinking. This was a decade after my drinking had got out of hand and the longest in that period I'd gone without a drink was a mere few days. My sleep pattern has never been great but it got worse after I stopped. I also quit smoking a couple of weeks later so my body was undergoing double withdrawals. My doctor suggested exercise and I joined the local gym. After about a week or so of daily exercising one night I slept for 13 hours solid (the only time in my life I can recall sleeping that long) and then after that my sleeping became the best it had been in my life to that point. Unfortunately I started drinking again a few months later and my sleeping was once again all over the place.
Anna's suggestion of meditation is a good thing too. Part of the problem with insomnia is that if you go to bed expecting not to sleep you can sometimes not sleep due to being unsettled and meditation is a good way to relax. There are also some free apps for iPhones that are good for relaxation. If you have an iPhone search the Apple apps store under either meditation or mindfulness.