Like, every day, every feeling, is reality. So everything you believe about yourself and your life are true. Then one day it changes, things are different, and you realise that it was a lie, and this new feeling, these new thoughts are reality, true, and you can't imagine you were thinking that your life was so good/so bad. Eventually it changes again, and you realise that , no, that time was a lie, and now is how you truly feel. And its like you get flashy-thinged by that memory eraser from Men In Black, so when your friends (who you've unfortunately gone talking to when you felt like killing yourself) are still worried and want to talk, you feel like a nob because now that feeling is a million miles away and you are just fine.
Then you realise you can never trust anything you think or feel about your own life.
And you stop talking to your friends to avoid embarrassment, stop making social plans in advance because you don't know how you'll be feeling, and whether the depression and anxiety will be back, making it so difficult.
Intersperse this with feeling 'cured' and like a fake, an idiot. And days/weeks of anxiety, feeling shit, feeling great, sleeping lots, sleeping less, angry rages, euphoric love...... Etc etc
Can't talk for everyone though, that's me.