Your wounds are still fresh, and it's very difficult even for kids who don't have tendencies toward OCD.
Yes, we're greyhound lovers, but does that mean other dogs simply can't compare? That they don't need loving homes? I've had equal numbers of purebreds and Heinz 57s, and I've loved them all. There are so many wonderful dogs out there, and they all need forever homes. I love greys because tempermentally, we're well-suited, but that doesn't mean that I don't think goldens or labs or Australian Shepherds or wolfhounds or standard poodles or the best of them all aren't splendid, too.
Give yourself time to grieve. It's nearly been 10 months since Millie passed, and I feel as though I'm just getting over the hump. I still cry at times, but it's been a tremendous loss. Her pictures are still on the fridge, her bag of food is still on the floor, her toothbrush is still in the bathroom. Time will heal but only you know if and when and what type of pooch you should have next.
One thing that has really helped me (besides the passage of time) has been watching That's My Baby on Animal Planet. It's really reminded me of the circle of life. I've also had a good time with AP's Pet Star. (Those Australian Shepherds are so smart that it's scary.) In other words, it's opened my eyes again to the incredible joy that our companions can bring.
Take it easy. It will get better.