dont worry those people who hadnt started the medical physics topic yet, although you undoubtably have by now. and the others who only have four people in their class doing medical physics as well. oh no, what will you do 3 other people to talk to as well as a teacher.
my teacher was doing astrophysics this year, because it related well into the cosmic engine topic (yr11) and its one of the very few subjects he knows about. so, i foolishly decided not to study astrophysics, probably because i didnt even open the chapters in our yr11 textbook that applied to the cosmic engine, and now im studying medical physics. without teacher help. or class help.
in short, you will survive, i dont know any good sites on medical physics but get helps of textbooks off oyur teacher and photocopy all the info, thats how i got throught the topic. i tried discussing it with my teacher, but ended up confusing him instead of him helping me. not that he ever really teachers or anything, just kinda stands out the front of the classroom and yells at us, reading from our textbook and showing slides from our textbook.
one good thing though, yesterday he watched me burn myself playing with mercury frozen by liquid nitrogen.