:O why has no one replied to this? WELL if you're still looking for incite then here we go, it could be that one of your ovaries has become well for lack of a better term "out of service" either because you harmed it in some way or it could just be a natural defect. That could cause infrequent periods, and then on top if it if you are over weight or do to many other factors you could also just be late on top of it. I would suggest going to a doctor and asking them about it they'll probably put you on birth control to kick start it, and make it more predictable. At that point if one of your ovaries is "out of service" you will have the opportunity to get pregnant every other month (depending on which birth control you take) It would be half the opportunity as someone with a regular period, so say your birth control lasts 3 months well then it would be 6 months before your next opportunity (that's just an example you'd want a month to month BC). I highly recommend going to the doctor though and asking, that last part I'm not 100% sure of but I feel confident enough posting it because my aunt went through the same thing. This being so late of a reply I hope you've figured out what it is, maybe an update would be in order yeah? To anyone else who might be having the same issue hope this gives you an idea of what might be going on. I know how things like that can be scary and you think something is horribly wrong with you if you don't know anything about it.