How can I be so devestated and be a good mother?

My husband died of cancer about 3 weeks agp. I am soo extremely heartbroken and devistated and lost and alone and every other horrible feeling possible. I just feel like I want to die. I am only 22, and we have a 2 year old son. I dont have any family were I live and his has always resented us being together so they are drawing away from us and making me feel like it is my fault somehow. I can't stop crying and I feel like I cant get through the next minute. How can I be a good mother this way?? I just am soo depressed. God gave me a perfect family like I always wanted and for some reason decided to take it all away?? I just don't understand it? I can't sleep at all, I am trying soo hard to keep it together for him, I just don't know if I can?? I try to not show him emotion, and tried to explain it the best I could to him, but I still feel like I am being a bad parent?? I am just feeling soo alone and devestated and now I feel I am being a bad mom??