I know how this is. My dog at 17 years old passed away a few years ago. Her and I both grew up together, i was a year older then her. She was my best friend for so many years.
I told myself I would never get another dog again, but 2 years ago the most amazing 'chug' (half chi half pug) walked into my life...literally, I wasn't even looking for him!
Things will get back hun. Just have to remember, she won't be in pain anymore.