I would be so heartbroken too. And wouldn't not be upset just because I didn't intend it. I think upset is exactly what I should be - some things are worthy of being upset over. I would question why the universe wasn't kinder to such an innocent, why it didn't protect such an innocent from me, and the only thing that would keep me going would be all the other beings that need me to put one foot in front of the other to continue caring for them. In the end the only thing you can do for sanity is to take every opportunity to remind others to be extra vigilant (as you have begun to do by posting here) - because maybe that will save another life, maybe multiple lives - and also remind yourself that your intentions were pure.
JJ
JJ