I am so sorry for your loss. I can't imagine the pain you are feeling. Do you have other people in your life that you are close to that you could spend some time with so you don't have to be alone with this?
I also think volunteering somewhere is a great idea. And maybe try to find a grief support group in your area?
Post as much as you need to, let those feelings out, even if you just need to say how much you miss him, there are a lot of people here who understand!