I have been working as a software engineering intern for the last 8 months or so. My job started in the summer, then continued into the semester. My employer's plan is to employ me part-time as an intern throughout the remainder of my degree, then offer a full-time position once I have graduated.
The last 2 semesters have been less than amazing. I enjoy my job, and I find the work to be very satisfying, but trying to balance work, classes, and homework has become a very big issue. I'm currently taking a standard course load (16 credit hours) of mostly upper-division courses, and then working around 20 hours a week (which is the amount of time my boss expects interns to work). Unfortunately, to get everything to fit into my schedule (which is unavoidably tightened by my living situation), I've had to schedule most of my classes back-to-back, without allowing me to take a break for lunch. Then I find myself up until 2-3 in the morning working on homework.
I was able to pull off last semester well enough, but this semester has proven to be extremely difficult, and it just got way worse. My midterm grades this semester did not meet my expectations for my own performance, and one of my professors just informed us that one of my courses would require around an extra 6 hours of expected out-of-class work.
At work, I've felt like my performance has been relatively good, given the somewhat limited hours I'm working. That said, I have had to take a few days off of work to attend to life, school, and student organization obligations (I hold a position in the department's student organization). I feel like my boss has been fairly pleased with my actual work output, but I have also observed that he's not particularly pleased with how many hours I'm actually working. Additionally, I have no guarantee that he's actually satisfied with my performance, as I have had no performance evaluations. When I'm needing to take a day off, he always asks if there's a day I can come in early to make up for lost time. The answer is almost always "no" since I go from class directly to work.
I've come to the conclusion that I will need to cut out a full day of work so I can focus on improving my grades, making room for out-of-class course obligations, attending student organization meetings, and just generally tending to my physical and mental health so I don't get [even further] burned out. How can I tell my boss that I need to cut a full day from my schedule when I'm already backed against a wall with hours?
EDIT: I should clarify on the student organization commitments, as I think I made that seem more invasive in my original question than it actually is. To be clear, those meetings are very few and far between. Thus far, this semester, I've only had two total meetings regarding the student organization. The meetings have been mandatory (budget meetings with the university staff, I'm the treasurer of the organization). My involvement with the organization this year is a little unavoidable at this point, as the organization is extremely small, and I'm the only eligible person to do the job. Apologies if I made it sound like the meetings are more invasive than they actually are-- those meetings were just on my mind at the time.
Additionally, the question of credit and payment has been raised. I am getting paid hourly for my work, but I am no longer getting university credits for my job (I was during the summer, but not afterward). That said, the employment is dependent on me remaining in school. Cutting back on coursework is entirely out of the question.
I appreciate the input received thus far, and I look forward to hearing more.