I strongly reiterate what the greekness posted, and I have a few more suggestions to make:

1. You must decide how much time you will spend at school after school. New teachers often fall into the trap of living at school until late in the evening, every evening. You have to leave. Set a time that you will leave every night, and stick to it. For a new teacher, 2 hours after school lets out is both realistic and the maximum amount of time you should be spending after school every day. After that point, it is important that you go home and do something besides school work. Even just taking a break for an hour or two to work out (or have a drink) is crucial to both your mental and physical health. This is probably the most common mistake I see new teachers making and the one that will lead to burnout the fastest.

2. You have to understand that it may take you a while to get things graded, and that’s ok. Unless your district has a hard and fast policy on this, DO NOT stress out about it. Your students may bother you about it, but again, you have to draw the line. It took me about 6 years to work out a system that worked for me, and I wish I had worked it out much sooner. Some things that have worked for me and for others: set aside half an hour or 45 minutes after school to work on grading, or maybe grade only one class period’s work, or even just grade 10 papers during your prep period. Make it a habit, and you will be done before you know it. Do not take work home unless you absolutely cannot avoid it – it can potentially get lost and you will work on that instead of relaxing like you should.

3. Find a hobby. I like to sew, some people volunteer, others work out, cook, go out with friends, watch movies, or play games. Whatever you like, make time for it at least three times a week to avoid burnout. Ideally, do something that uses a different part of your brain than you use while you teach. All teachers can identify with needing time to themselves after school. You are in a profession which requires you to be in constant communication with needy and demanding people who need you all the time. You have to make time to decompress.