Invisible

I'm coming and going I think im just gone. I'm weak and tired,days are too long. I'm up and I'm down my mind isn't sound I'm here and I'm there but still can't be found I'm in and I'm out but yet don't know my way I'm here and I'm scared of the very next day I'm rising and falling ,my pain gets my nerves I'm screaming and shouting but still not heard I'm stopping and going my tank is on E I'm smiling at you,you're looking through me.