Maybe you are looking for jobs in the wrong area. I don't know much at all about that field of work, but if you can have a job at a hospital and you love kids, maybe you could find a job at a children's hospital. It could benefit you since you have a little one yourself.
If you wanted to become a nurse because you liked the idea, then stick to it. You will find disgruntled people in EVERY career path. Teachers, doctors, truck drivers, McDonald's, accounting, everywhere. Those bad attitudes will only become yours if you allow it to. They are disgruntled for their reasons and you might become so for an entirely different reason.
In regards to your little one draining your energy, well what did you expect? That is what ALLLLLLLLLLLLLLLLL parents feel like. That's part of being a parent. Where is the father? If there is no father present, I guess you could start looking for a guy who doesn't mind baggage and would help raise the baby.