Is it okay to have a drink tonight?

My daughters are 3 and 5 and today I have SUCH a craving for blackberry brandy. If I go out and buy a bottle,would it be okay to drink it when my children are asleep? I haven't had a drink since I got pregnant with my oldest daughter but today,for some reason I just want a drink SO badly. The only problem is,I'm a single mom and I'm worried that if the drinking makes me tipsy and one of the girls wakes up,there will be no one to take care of them and I'll never forgive myself. What should I do?