I hate myself!!!

I am suffering from severe postpartum depression, I am on medication and have talked to my doctor about it already. I get so depressed that I just cry for no reason and just wish I could disappear, telling myself that I am a horrible mother and that my kids would be better off. Looking at me you would never know the battle going on in my head as I force myself to smile every day for my kids. But I still have these feelings and then I look at my beautiful children and hate myself even more for having the thoughts that I do... I just don't know what to do, I mean look at these beautiful faces and tell me how anyone could have the thought of leaving them...