Med school (at least the first two years) is tough, but not altogether that much different than undergrad. You're just expected to know more and your knowledge is valuable not just for getting a good grade, but actually valuable for you career and knowledge as a practitioner. Well....for some classes at least.
We're constantly having mixers, fro-yo outtings, happy hours, house parties, museum trips, random weekends in Vegas, Tahoe, etc. I actually study very little on weekends and usually reserve them for downtime and relaxation, and usually trips to hang out with non-med students. We're lucky at my school in that we don't have periodic graded exams (outside of problem sets and open book quizzes)...meaning it's possible to wait til the end of the quarter and just cram from everything.
Med school definitely has a high school feel to it...wit various clicks that form on various lines (ethnicities, background, undergrad institution, even the surgeon vs. medicine groups of people....for real). To be honest, it annoys me sometimes...but no one said you can't still maintain outside of med school relationship even though you're a med student. I've sort of made this a priority for my med career and I've been happy with it so far.