It's actually good to hear that the saddest day of your life involves something gettings stolen. There will be much worse days. I guess what I'm trying to say is that it's just stuff. It's sad, but don't let it get to you too much.
I'd bet >10% of the readers here have had any of the following: Cancer or similar shitty disease or disability in self or family, lost >50.000$ in natural disaster, accident or financial turmoil and/or are in a permanent state of stress due to job, relationships, legal battles or similar.
Perspective!
At some point later in your life, someone you dearly love will die or be severely injured. Or you will witness something tragic. Then you might reconsider what is your saddest day.