Ang, I'm so very, very sorry for your loss. I agree with Tina, anniversaries and birthdays are always hard. In some ways it must feel like it's been forever since your nephew has been gone; in other ways I'm sure it feels like it was just yesterday.
My best friend lost a young niece about five years ago when a tractor-trailer truck that had not maintained its brakes slammed into the family's car. Losing a child in the family is the most primal of griefs. Even now, this many years later, it can cause my friend intense pain. But one of the things that she did that helped her more than anything else was to find a support group, like you want to do. When you have lost a child in your life, sometimes the only people you want to be around are those who really, truly know how you feel.
Can you tell us where you live? Would you like help finding a support group in your area? Feel free to answer here or to answer me in private by clicking on my name (in orange up above this response) and sending me your city and zip code. I'll see what I can find for you.
In the meantime, hang in there, and realize that you are doing well even when you are just getting by. This is tough, tough stuff.