Crying out to God

Ever since I became pregnant with my second son I have been battling depression. It was a hard pregnancy and even though I love my sons more than anything I can't shake my depression. I have everything in the world to be happy about and I can't be happy. I see a Doctor (who is a Christian) and take my prescribed medicine which helps but I still feel like I'm in a hole. I cry out to God constantly for help. I wonder what is wrong with me. Negative thoughts invade my brain daily. I wonder if God has stopped listening to my prayers but I know that is just the devil trying to break me down. I must say he is doing a good job of it. Making me doubt myself, and even hate myself. I do know that God is there and in the back of mind I know he is listening and working in His own way. But that doesn't really make me feel better. I feel like a failure. A complete failure. My family is wonderful and they help me a lot but I still can't shake this feeling. It's like nothing in the world can bring me out of it. I feel selfish for constantly praying for myself like a baby crying out to God but I do not know what to do. Please pray for me. I am lost.