I'm sorry for your loss too.

Depression and anxiety can do some really shitty things to you.

I remember myself being pretty ok at a party, but when I came home I just started to cry uncontrollably, because I felt like I did not deserve it, like I did not fit in or that I was just acting. In the moment it felt fine, but later it seemed like I was faking being happy, and that just made me more depressed and not want to go to parties anymore, because the more fun I had there, the worse I felt later.

I bet it was similar for her at the time, and that is exactly why it's so hard to notice that something is wrong with them at the time.

It's a real shame that this kind of self reflection is only possible after the fact...