Hang in there, DM. I know things are really awful – you just have to take it one minute at a time. After my mom died it seemed like the whole world was grey but it slowly got better. There were times even months after her death when the sight of a cardinal (her favorite bird) would make me cry. And there was weird stuff with my younger sister. I tried to remember that everyone handles grief differently and her reactions wouldn’t necessarily be mine (or any other sane person’s, for that matter. No issues here 😉 )
I found hugging my kitties (and my dog) worked the best. Maybe it will work for you. It is very calming to just sit and pet a cat.
We are here for you, DM.