It's not taking the classes.
It's picking the classes for your next semester. You gotta make sure you get class times that work well with your day, good professors, and all the classes you need to transfer/get your degree. Especially when you're trying to balance it all with a job, you need to find a way to get all these factors to fit in right.
At the same time, this is probably the best thing about college. Thanks to
http://www.ratemyprofessors.com/ you don't have to worry about getting that one teacher that you just can't stand. You can set up classes at times that work for you; if you're a morning person, you can choose early class times, or if you have a job during the day, you can take your classes at night. And of course, you get to take many classes you might actually enjoy, since you choose your major.
I got a bit off topic.. but yea. This stress is killing me.