I'm sorry for your loss. When we had to put our cat to sleep, I thought I would be stoic and strong. As soon as it was final I broke down like a blubbering baby, and kept at that for a solid 20 minutes. I thought that was hard until a couple years later when we had to put our most precious little doggy down. That had me wrecked for weeks on end. I'm still not healed from that loss, and it has been six months. We occasionally talk about getting another dog, but I don't think either of us will be ready for quite a long time.
Anyways, it does heal, but you'll never be the same. I'm sorry for your loss.