I spent the majority of my time in college working part time, like 20-25 hours a week while I was attending classes. I think most would concur this is fairly typical. When I got out of college (and for a gap year that I had in the middle), I worked 40 hours a week, and it was fucking awful. I found that my productivity plummeted, my diet and sleep schedules worsened, and my overall happiness lessened. I returned to a post under which I was previously employed, and am now working only about 20 hours a week. This, I would say unequivocally is the happiest I have ever been in my life. I am well rested, and get enough time off of work to where I actually look forward to it, not towards the weekend. When I arrive for my shift, I maintain maximum productivity for the full duration of it (I work 4 5-hour shifts), and am the star employee on account of this.
Our bodies are not designed to handle 40 hour workweeks, from a strictly biological perspective. I attribute a large degree of the malaise we have in human civilization towards our collective acceptance of the 40+ hour work weeks. Do yourselves a favor: get roomates, apply for medicaid, and live for the moment. Don't toil at a job you hate for a future that may not be there.