I've had this a few times in my career. It typically comes from being stuck between a rock and a hard place. On the one hand you are not suppose to work such long hours (they don't like paying you for them or it clashes with their policy of maximum hours) and on the other the work needs to be finished to a certain standard. Your coworkers managed to handle it, so why can't you?
Except...that was not exactly the truth. I asked my coworkers and they said they were working the same hours as I did, but wrote down the standard 40 we are all contracted for, so they basically worked for free just to get their supervisors off their backs. This alleviated the pressure a little, but they were all still hovering near a burn out and some did, same as me.
In a way, it was my fault. I tried to live up to impossible standards and conflicting requirements. I often let my frustration over this impossible situation get to me and endlessy tried to plead with my boss about how it wasn't workable and not sustainable. Yet, I kept fishing those chesnuts out of the fire and somehow got the work done, but at increasing expense to my own well-being and free time (though I never lied about my hours).
Why did I do it? I still don't know. I do, however, know that the situation was not off my own making and it would have been over a lot sooner if I had just let things burn and let the responsibility lie with my boss, where it belonged in the first place.
I ended up leaving and changed my attitude for my current employer. I started as I meant to go on. So no rabbits out of hats and I will not be putting out fires, as that is not my job. I do not get paid for that kind of responsibility. Sometimes I get a supervisor who will complain, but they only do it once, as I refuse to change. I also have moments where I fall back into my old habits (fundamental change takes time) but I have gotten a lot better at recognizing the feeling of frustration. Instead, I now focus on identifying the source of the frustration and dealing with it. I am also prepared to let things burn.
Ultimately, none of it will matter after I leave. I am not saving lives or preventing wars. Few people will remember me once I am gone and I find that I am actually good with that.