I can tell you from firsthand experience how stress affected my life. I have been working in dialysis since graduation (well, technically 6 months after graduation; jobs are hard to come by). I recently made the decision to go back to school full time. It could not be a more perfect time, because I was DONE with my job. My manager gave a bad name to managers everywhere and the patients had no respect for any of the staff due to the lack of management. I was lucky to find my "way out" when I did. My health was starting to suffer and so were my relationships. I am 23 years old and I was in bed by 7:30 every night.
Anyways, as for preventing the situation: know your limits. I know that it is difficult making a decision like this. I had reached my breaking point and had to leave my job. Don't let yourself get to the point that I got to. I tried to "hang in there", but it was not right for me. If your gut is telling you that something is not right, it probably isn't. I know it can be hard leaving due to the lack of nursing jobs. Sometimes it's the best thing.
Another recommendation would be to look for a mentor. I had no mentor at my job and basically learned from the travel nurse who was there for 4 weeks and taught myself the rest. Having a mentor who will help train you and be a "shoulder" for you will be a better asset than you will know. Have good nurse friends who can listen to your issues will help, too. Friends and family help, but they just don't understand like other nurses do. Hope this helps you!