You know that being a mother is the toughest job, ever. I wasn't a single mother, but my husband was in the military and away a lot, so I know how you feel. I didn't drink at all in those days, and what got me through was learning to meditate. After lunch would be quiet time for the kids, and that was often Sesame Street. It would give me fifteen to twenty minutes to myself to just 'be' and it really helped.