Those medications are designed to reach a certain level in your blood and stay right around there all the time in order to work effectively. Taking them only 5 days out of 7 and skipping two days in a row makes your blood levels fluctuate and they simply won't work as well.

Plus, alcohol is a depressant, especially in binge amounts. You are adding to your depression at the very same time you're not taking your anti-depressant medication.

If you keep doing this, don't be surprised if your mood disorder doesn't improve at all. You're actively sabotaging your treatment.