Our normal course load is '4' courses per semester. This was a 4.5 course semester, but it was the courses themselves that killed me.
Chemistry Lab for Junior Chemistry Majors: This included a 1.5 hour lecture every week, 6 hours of lab every week (that usually became more like 6-15 hours of lab), 5 lab reports (with extensive experiments) that were 5-6 pages long each, about 5 challenging problem sets to go along with the weekly lectures, a bigger experiment with a 15-20 page lab report, and a final independent research project and lab report that was 20+ pages. This was all in one semester, but since I went to a liberal arts school, it counted for just as much credit as intro to psychology (3 hours of lecture/week). Yeah.
Physical Chemistry: This had a calculus III prerequisite. I did terrible in calculus III and did not have much of a background in physics. I struggled for this B.
Physics I for Pre-Meds: Maybe not as hard as the accelerated one for potential majors, but very challenging for me, since I had no previous background in physics. Most of the students in the class had taken AP physics of some sort. Plus, I was swamped by other stuff and just didn't have much time to study.
Intro to Economics: I was told this was an interesting but easy course. Unfortunately, I got the one professor who was considered to be not easy at all. We had about 100 pages of reading a week (including articles) and completely finished our 900 page text book, easily. He was a great 'teacher' but my god I just didn't have time.
Biochemistry Research Course (1/2 course): My research adviser was about the only understanding professor I had that semester.
I think my parents were extremely exasperated with me. I called home sobbing several times. Luckily, other people were in the same boat as me, and I didn't come out of that semester too worse for wear. My dramatics were probably for nothing.