Things In My Brain

I feel not okay about feeling okay

"How are you?"

I freeze up whenever somebody asks me that question, because I don't know the answer.
My first instinct is to answer "I'm okay" or "everything's fine" because I usually feel like that at the moment but then my mind immediately goes to
am I really okay? Or am I just saying that? How am I really feeling?

And then I fall into a fit of existential panic and dread and end up making myself feel not okay about feeling okay. It's as if I don't ever allow myself to feel at ease.
If everything's fine, then something bad is bound to happen eventually, right?
I'm so used to repressing my feelings that whenever I feel okay, I always assume it's a cover up for how I "really feel". I'm so used to lying to myself and others that I can't even trust myself anymore!