So sorry to hear you've lost your special girl. Although you know you've done the kindest thing for her, it doesn't make the separation any easier for you. I've been there twice and the pain is the same as if you lose a member of the family, which of course she was. It does get easier, I promise, and there will come a time when you can remember her and smile instead of feeling the grief and emptiness that you do now. Be kind to yourself and give yourself time, the sadness will fade but the memories will always be there.
Run free Bracken!