PCOS?! 19 and I've only had 4 periods in the past year!?

I have a lot of minimal health problems. I'm 19 and I seem to be fairly normal. I was active during high school and I try to stay active between my waitressing job and school. I have been diagnosed with iron deficiency anemia- on a moderate to severe level. I also have a few other vitamin deficiencies such as B vitamins and magnesium. In the past year, I have had 3-4 periods, July 2012 September 2012 October 2012 May 2013 I always get scared that I'm pregnant, but I am very safe and my tests are always negative. I worry myself constantly over this... but the more research I do, the more I realize that I have the majority of PCOS symptoms. I have gained some weight since I noticed this, but it could obviously just be the "freshman 15". Lately, I've been sleeping a lot. Probably around 14-15 hours a day including naps. I feel irritated with other people and (I'm not sure if this one has anything to do with it) I'm always hungry. I JUST ATE like 2 hours ago and I could eat again. I get period symptoms, PMS and during. Right now, I have leg cramps (normal period symptom for me), cravings, tiredness, acne (I typically have an incredibly clear face), and I'm moody. Advice?