Two things come to mind right now. First, when my husband is sick, for some reason, he get's angry easily. Under normal circumstances he's one of the most calm people anyone knows so anger isn't a part of him. Looking for something in the fridge, it had the audacity to close while he was still there and the outburst was something to see. When life disappoints us, we deal with it. When family and friends disappoint us, we deal with it. When our bodies disappoint us and the fix is non-existant for far away, we have no where to turn. A mounting frustration turns to anger which when turned inward, is depression.
Currently, add to this is a questionable mammo! Having a recent 'scare' myself, I know this is all consuming, especially given your personal history. Your back, quite a major crisis in your life, takes a back seat.
So, how do you cope? First, take it one day at a time. Even if your back takes too long to heal, you are moving forward, no longer stagnant. Then, just as you dealt with it before, you'll deal with whatever else comes your way - getting through each day by concentrating on the day at hand. Suffering - yes. Needless - yes. Doable - yes.
And look, just yesterday we were wishing everyone happy holidays and it's already February! At this rate, Thanksgiving is just around the corner
My best to you, Dale