When i'm down and people snap at me... i feel raw. like my skin isn't enough to protect me.
i suppose in an ER ppl are more brusque due to time factors. snappy is a stone's throw from brusque. and some ppl let off steam that way to stay afloat themselves, at the cost of others. then there are just plain old snappy people. Those and the steam engines are the "its not about you" people. But they hurt just the same eh.
i understand feeling like a failure. Fwiw, i really admire you for even taking on such an endeavor - so faaaar from a failure. You sound in a tizzy and exhausted. Are 12 hour shifts

frequent? I wonder if you have been able to bond with any other nurses, to see if others have been through this.
I've asked before I think, but... why this job or, specifically, in ER? Can you reduce your volunteer hours for now?

My heart goes out to you.
Remember
your health is even more important than your work, let alone the number of hours. PLEASE REST. Today, tomorrow, the day after, andthensome. Please take care of yourself! (Nurse yourself!)
hugs and a drop of lavender

on each temple (relaxes)
~ waves ~
~