I'll be frank with you. You will know when it's time. Everyone has a boundary or limit they reach. Some is instant, it occurs to them in the work place, in the moment and some gradually. If you feel this way now, unless anything is being done to make it better, eventually you'll get to that decision. It's sort of like being in a marriage that is very roocky and problematic, you may think about divorcing but not know when or how to initiate that journey, but if marriage counseling, couples therapy , prayer, whatever isnt being done to turn the situation around, eventually could be monthss from that moment or years, the end result will not change. Divorce will be the resort.
so in your case. you can keep wearing out till you finally have none left then leave, or strengthen up and understand that the issues are on the patient care side, and that realistically isnt going to change anytime soon so you have to make decisions from your end and what you know you need.
You may not be with that steady income any more, that is the truth, and you may not live as comfortably as you are now financially, but you will have your sanity back, and learn to live healthier and better. It's a matter of choosing what you need now. So many nurses I see so stressed out and worn out, being worked, instead of working, letting the money make them, instead of making the money. Best of Luck.
*personal healh has no price. In the end, we are not taking all this with us. To care for others you have to simply care for yourself first.