How many hours a week do you work? Check the labor laws in your state too... there should be caps to how late you can work on school nights and weekends and how many hours a week you can work at all.
As for dealing with the long days, that's more of what I have to deal with now rather than in high school. I worked in high school, but I went to cyber school so it worked out easier for me. Now I work an office job up to 30 hours a week during the school year while I go to college. It kind of stinks, but hey, I need money.
My suggestions would be to work ahead at school as much as possible on weekends (or whenever you have off) so you're not so stressed the days you work. This may be easier said than done, but you've got to learn to make it a priority. Also, keep reminding yourself WHY you're working. Saving for a car? College? Spending money? etc. Think about the power and independence making your own money gives you. And if you really hate your job don't forget there's nothing stopping you from looking for another one! Search or keep your eyes out for something else you might enjoy more; it really make the time go faster.
Finally, and for me most importantly, make SLEEP a priority! You'll be useless for your working responsibilities *and* your school work if you're too damn tired to concentrate. Caffeine only goes so far!
Best of luck.