I have no recollection of ever hearing about that happening sorry if you feel misled, that was my twisted sense of humor surfacing (Wayne has not completely killed it, yet). But, there were a few times last year (usually right after I got done taking an exam) that it had a certain appeal.
I am sure that there is a med school somewhere out there that has lost at least one student to suicide; but I think that if you can keep everything in perspective you shouldnt worry too much. Just think of how hard you worked to get into med school, all of the people that did not get in that would love to have your seat in Jaffar, the thousands of other first years across the country that are going through the same hell, and that like most things in life this too shall pass (and hopefully you will too, so that you dont have to go through it again).
Re: second year vs. first year. I seem to recall speaking with a member of the class of 2007 (a second year last year) who said that what he felt was the worst part of second year is that that isnt a light at the end of the tunnel that you are seeing it is a train (I think he was referring to step 1) bearing down on you.
One other thing, it is more important to pass the courses than the exams. Since it is possible to fail an exam (as long as there is at least a second one to pull your score back up) and still make it through the course.