How do I get out of being depressed?

Well i have recently had a beautiful baby boy, no his father is not in his life and does not want to have anything to do with me or my son. I thought that we were n love but he has ony brought me heartache and pain. Im not really hurt about how he treats me cuz that doesnt matter but im more hurt because he denies my son and treats him like crap. Some days are worst than others. Sometime i never get out tha bed and hen there are days when i dont want to b bothered wit my son and i kno that sounds bad but im just not happy. I luv my son but im goin throught alot in my life right now and i ust need to kno if theres anybody out there who is goin through what im goin through then maybe they can give me some good advice.