Like, we dont know how anyone else is feeling so can some people's normal actually be super depressed and no one even knows it and they think they are fine?

Yes. As long as I am able to work, even if I have no interest in anything and no enjoyment whatsoever, I will ignore my emotional condition and persist. It doesn't occur to me to care about that because I don't really expect anything more.

I was given a new medication some months ago that didn't help whatsoever, and I didn't even notice it wasn't helping until I lacked the motivation to refill it and realized that withdrawal felt much better. I would have said "Sure, I'm fine" that whole time as well.