I'm definitely no expert, but something similar happened to me my senior year of high school. I was a role model on the color guard, matching with a knee injury, and trying to get in to a really prestigious liberal arts school. Long story short, I was exceedingly stressed out and didn't have my period from July until November. I got it back by consulting with my mom's OBGYN. As a virgin, this felt really awkward for me, especially because he was the doctor present when I was born, but he gave me a ten-day prescription. He said that if it didn't come back by the time I ran out, I would need to come back for tests, but otherwise it was simply stress-induced. From your post, that's what it sounds like to me, so if you really want it back I would visit your OBGYN. Personally, I wish mine would pull another disappearing act. My last cycle during school had me in the infirmary for a shot of phenegrin. If you don't have that kind of problem, though, then good for you and best of luck.