Life as a nurse?

I am fearing that when I start my training or job as a nurse, I may feel burned out. Whenever I see staff nurses doing their duty, I can feel their tiredness but that doesn't show in them. I wanted to be a competent nurse (I'm a newly RN) by working at a hospital and improving my skills. But here in the Philippines overtime is normal and part of the working hours and I fear that I may get drained and will not be able to perform well. I'm thinking of some things like I may not really like this job that's why there's something holding my back, or maybe I'm not yet prepared and new to have experience first. I'm an introvert and I think this affects my performance when I was a student; my enegry easily needs to be rechanneled immediately. How can I resolve this? Hoping for your good answers or opinions.