I've had this once, in the middle of a car accident, while things were still unfolding, and that thought was "this is going to suck".
It did, in fact, suck, though, not as much as I'd imagined I suppose. Car was totaled, I walked without a scratch, went to the ER where they handed me a scrip for 30 800mg Ibprophen and 30 Vicodin, and then told me I could call the doctor's number on the scrip if I needed more Vicodin....
I wound up just going home and taking a couple advil, went to bed, and woke up feeling like I, well, had totaled a car, took a couple more advil, and that was that.
Funny though, how, at our most vulnerable, there's an odd clarity about it, none of the day to day BS in the way, quite literally living in the moment, which may be your last.