What you say:

I'm fine

What you expect people to understand:

I hope you know that I'm never okay, I just need you to reassure me that you still love me and probably bring me a bucket of flowers.

You expect people to have telepathy ability? Like what happens in novels? A guy can suddenly be all mind-readers and say "Wait, I know you not okay. I can see it from your eyes, you're different."

Look, as much as I want to say that I'm a severe idealist, those craps NEVER happen.

What you need to do is grow up, speak your mind when you need to.