I have extremely irregular cycles

I have seriously irregular menstrual cycles. I can go about 2 to 3 months without getting a period and when I do I get extremely bad cramps to the point of passing out and the period lasts for upto 7 days, on a quite heavy flow. I don't really have consistent eating habits could this be the main cause? I'm really scared at the fact that because I don't have a consistent cycle at all (I'm lucky to get it once every other month), does that mean I won't be able to get pregnant?
What can I do to make it a more reliable cycle, because I honest to god can't tell when I'm due on, and it's even worse being sexually active with a boyfriend because there's continuous pregnancy scares.

[kephartswife20]

i know how u feel..but i used to go 5 months with out a period then when id get it, it would last up to 5 WEEKS...yeah...i would guess it was my weight and the fact that i had reacurring cyst on my right ovary.the funny thing was the heavier i got it started to regulate...have u ever been checked for cyst?...i had to get my right ovary removed at the end of July then had my regular 4 day period then got pregnant...lol..idk i would ask ur dr. about it. he will do tests and maybe put u on the pill for a while to try and regulate it.

[tarajanes]

It sounds like you dont ovulate every month hence why you dont get regular periods.best bet is to see doctor as previous poster said,they can run tests and put you on the pill to regulate your cycle.it is still possible to concieve (conceive),but alot easy if your cycle is normal.