What do I do if I have terrible sleepless nights if I don't drink alcohol?

Actually, alcohol is well known to cause sleep deprivation. You may feel after a large quantity that you have a long night's sleep, but you inevitably wake up feeling tired the following day - this is because excessive alcohol reduces the quality of your sleep, preventing you from getting into the "deep" sleep you may otherwise on a sober night. If you can get through a few sleepless nights to actually quit drinking, you'll find afterwards that you're sleeping a lot better. If you quit drinking and you still have insomnia, talk to your doctor about your options.