I am so sorry for what you're going through. It must be so difficult for you, especially since you seem to be going through this alone. You need to get some support. Considering the circumstances, CPS might be involved with your situation - ask them for counseling resources. They might even be able to pay for counseling for you. If they don't, you might be able to get help through your local domestic violence program or Hospice. You shouldn't go through this alone. I'm sorry your mom isn't able to support you - she may be dealing with her own feelings about her grandchild's death and just not emotionally available for you right now. But your feelings are real, and I imagine all of us who have lost children wish we could exchange places with them.
Hang in there sweetheart - you will always be Adden's mommy..