I am sorry I know how you feel, clearing their things away seems so alien, and final. I went down that road last week when I came down and found one of my foster cats, who had been poorly for a few days, had passed without me there.
I did have a post mortem examination done as he was not an old cat, and it helped me to know it wasn't anything I had done wrong, and it wasn't anything contagious. But I still wished I had been there for him, I hated the fact that the holidays were there, and we were waiting to do some further tests on Tuesday. But he didn't even make it through Monday, so sadly it was not to be.
Daisy your family loved you so much, and are hurting, but they will remember the good times soon , and those times will make them smile.