Best thing to do is remember that those memories don't exist in the house, they exist in the people you shared them with. When my Grandma died and her house was sold it was really hard having to watch it messed about with. They tore down the old conservatory, bricked up a window (and I dread to think what changes have gone on inside) Because I live so close to it I found myself staring at it every time I went by - I still do sometimes.
I never took any pictures of it, but in a way I'm glad I didn't. Sometimes it's nice to see the house in your mind as you saw it in in real life. I was still young when my Grandma died, so I remember the stairs being so steep and narrow, and the bed I slept in being massive. If I was looking at these things in a picture they probably wouldn't be the same.
My advice would be to go round the house one last time (if that's an option) and take it all in. Go to each room, go through all the good memories and even the not so good ones that happened in that room. And when you leave the house, take one long last look at it before you go. But one you go don't turn around to look at it again. That house will be a memory to you now. It doesn't matter if it's knocked down or changed beyond recognition, because it exists to you as a memory. It's a great memory, but you don't have to dwell on it every second of the day.