I'm so sorry for everyone's losses. Sophie, I can relate. When my cat, Chica, died, I spent days sobbing and missing my dad - he died on my 10th birthday, so many, many years ago, but it brought it all back. I still miss him even though I never got to know him as an adult.
Lost my mom when I was 38, then the downward spiral began. Within six months, my ex, my brother-in-law and a coworker, all committed suicide. After that, another ex and a close friend both died suddenly. In 2006 I lost my dear sister and best friend. Over the last three years two close friends died of cancer on the same day. One of them I swear I have been in contact with (also my sister, both via birds - another story). Also my son's father died of cancer during this same period. He was alone, living in another province, and my son and I had to make the arrangements. It was really hard on my son, as he hadn't seen him for some time and was planning a visit within days of his death.
Last week I found out another friend passed. You never get used to the empty, hollow feeling when you lose someone you care about. As we age, we realize how immortal we all are. I give thanks every morning that I'm still here and in reasonably good health.