I took a full AP/honors load at what was, at the time, the most highly ranked school in my state, and participated in dance, chorus, and science research and competitions, and I still had plenty of time to just hang out with my friends and go sailing and play D&D on the weekends, and I made 5s on my AP exams. I graduated...well, let's just say, even earlier than you, ultramarina. My AP courses actually had a lighter load in terms of the volume of work required than the regular track college prep classes at my high school, but higher expectations in terms of depth of understanding, analysis of the material, and quality of work products. They were much more like college courses than high school courses in this respect - which is, after all, what they are supposed to be.