I've been through 4 longer term (3 - 12 years) relationships in my life. Because of my upbringing I do much better when I have a mate to come home to and work towards the future with. When the end comes it's like a shock and there really is no way of avoiding the pain, just distracting it for a while. Your world has been turned upside down. I have found it's helpful to try to maintain as much of a healthy lifestyle as you can. Make your self eat at scheduled times and if you cant eat force down a good shake. When your body doesn't have the necessary nutrition it needs everything else gets amplified, including the emotional pain. Train as often and as hard as you can. The endorphins will lift your mood and just as importantly you'll have a better chance of sleeping. Not enough sleep and it all gets amplified as well. Do not look at pictures of her, ever. If you like dogs and miss yours then get one, they are the best companions you can have and you'll have to worry about the care of something else that you will eventually love. Find things other than yourself to occupy your mind and energy.
I had a pretty rough upbringing as a kid and have suffered through periods of depression in my life. During one of those periods my grandfather came to me and said "I know that you are depressed, but to help with it you have to stay busy". My grandfather grew up through the great depression and his belief was that a man's worth was measured by how much work he did. Thus, I thought my grandfather's advice was nothing but an idea from a very different time, a time that had no application to my life. Since then I have come to realize how very right he was. I was just too consumed with my own suffering to acknowledge it. I'm not saying that you are going to fall into clinical depression, but you are going to suffer. To get past it you will need to feel it, but not all the time. As much as you don't want to because of how you feel, do something with your spare time. Sitting in front of a TV isn't doing something. Take up some kind of hobby or learn a skill. Archery, wood carving, renovate a room in your house, anything productive that makes you feel like you have accomplished something worthwhile. I'd also suggest that you use a heavy bag to release some of your emotion. Certain emotions create unpleasant chemical responses in the body which are burned up with striking and you will feel much more grounded and clear.
Some folks suggest finding someone for sex right away to help move on. I personally believe that you need to spend some time alone working on your own healing and not relying on others to give it to you. By all means when you feel comfortable doing so start dating again, though IMO the last thing that will really help is banging some one nighter or casual while you are so vulnerable. That one nighter/casual could become a crutch that ends up being a nightmare that turns you jaded for a long, long time.
You will get through this Brother. This to shall pass.