I got pregnant at the beginning of August, so IF you were pregnant you'd be due here in the next couple months. Have you been to doctor and discussed any concerns with them? Have you gained weight or got a belly or anything? I used to only have 2 periods a year, if that, and it turned out I have Hypothyroidism, which throws my body out of whack, but it's nothing too serious. I'm not saying you have it, but you definitely should go to the doctor and talk with them to figure out why your period is no longer there. It could be something minor, or something serious. I hope everything is okay with you!!
My periods are always hit or miss. I can go months without one but not sure why. Pregnancy is a possibility. With both of my boys I never gained any weight or anything. I never looked pregnant or had any of the ' signs' except heartburn. So you need to get a test asap and if your not then call your doctor to see what's going on. Good luck!