My most difficult quarter in college (engineering program) I was only taking 12 hours of classes and two labs, but I was doing homework on average for at least 6 hours a day during the week to cover three of the classes and the 4th class was almost always a Sunday project of 4-6 hours on top of the normally required homework in the other classes. I didn't study from Friday night to Sunday morning, with a few Saturday evening events in extreme circumstances. That quarter kicked my butt. It was literally go to class, study, sleep, eat, work for 3-5 hours at night and a few potty breaks.