PCOS stress

I'm almost 20 now and I haven't had a period since Feb. of 2013. I was diagnosed with PCOS when I was 11, because I was fully developed but hadn't started my period. Even then, I didn't have my first menstrual cycle until I was 15, with the help of progesterone and birth control pills. After 3 months on the pills, I quit taking them but my cycle stayed regular and on time for the following 3 years. I thought my period had stopped because I was under a lot of stress at the time, but now that my life has evened out, it still hasn't started. I went the the hospital/doctor on three different occasions about my missing period and no one could tell me anything.

Now, and for the last month or so, I've been cranky and crampy. My abdomen feels full or like there's a pressure there. I've had to urinate more frequently within the last week than normal and my breasts are more tender than they used to be (they're always pretty sensitive, but never this sensitive) and I think they may have gotten bigger. I've also been having nausea and vomiting, which is exacerbated by heat and physical activity, but will come on even if I've laid around the house all day. Some days I can't eat at all because I know I'll get sick if I do. I'm always tired and more emotional than usual. 

My boyfriend and I don't use condoms because I have a sensitivity to them, but he up until two weeks ago he would pull out (TMI, I know). I thought I couldn't get pregnant because I didn't have periods, but could I be? I really need to know what to do or where to go because I don't lead the healthiest of lifestyles...