I totally empathize. It's the same for me. I remember the experience just enough to describe it but at the same time it's almost like it was happening to a different person. I can feel other memories of times I was happy or in love or what have you (though admittedly less intensely) but the memories of depression are just different.

There are a lot of things in life you can't understand until you experience it and so the best we can do is teach others empathy and just educate them as best we can on what we go through, why it comes about, and possible treatments as well as how to not treat a depressed person like they're somehow handicapped but instead just ill. Ignorance is what drives the prejudice and the "just snap out of it, you pussy" type of comments.

Great book recommendation too! I read that book when I first sought help and it's really spot on. Most psychiatric professionals recommend it and I would argue that it's the gold standard of self help books for depression. I don't even like to call it self help though. It's really partly self help exercises mixed in with education. It's definitely not pop psychology and is based completely on solid science. Maybe people you recommend it to think its another pop psy book full of pseudoscience. It gets updated pretty frequently too. Great book.