Insomnia

It is easy for most people to understand how stimulating substances like nicotine may interfere with sleeping. Insomnia can also result when a nervous system "depressant" (such as alcohol) wears off. During your exposure to alcohol or another nervous system depressant, the brain produces extra chemicals that have stimulating effects in order to help you to compensate. When your alcohol (or any other "depressing" substance) wears off, your natural brain stimulants are still active. Insomnia is one of the most common symptoms of alcohol withdrawal, and it can occur even with modest regular alcohol consumption.

You should abandon habits that are not healthful. Your sleep will benefit and so will your overall health.