No air

Sometimes I just feel like I can't breathe. Like there's no room in my lungs to let in air and no strength to even take in that breath.
Every day I sit here in silence surrounded by my equally silent colleagues and want to scream or swear. I don't like to talk to people any more. I won't sit in the staffroom, and if people ask how I am or say hello then I smile and lie and scuttle off as soon as possible. Hibernation-mode. I don't want to share and wouldn't know how to share the way I feel. Mostly I don't want to share. They'd try to be nice. They'd try to understand and they can't understand. I don't want *them* to understand. I want to be left alone. Except I don't. I think. I don't know.
I feel suffocated. And so heavy.