re: Is school more stressful than the workforce?

It all depends.
In some ways it is and some ways it isn't, and it varies by career.

One thing that is easier about working is that when I'm off the clock, I'm off the clock. With school, I'm always working towards a deadline whether I'm in class or not. I'm never "off the clock", especially close to finals. Now, some careers don't get that luxury, but in careers where one does, it helps a lot. It allows you to compartmentalize your day and not let it affect your relationships nearly as much.

However, work has real-life consequences. Ooh, you failed a test? You might have to repeat that class, lose your scholarship, and your dad will be super cross with you. Depending on your field, a f&%k up at work could result in people dying, lawsuits, jail time, people's lives being ruined, the company going under, or losing your job. The consequences can be so much more ruinous.