Why am i getting frequant periods?

For the past two months i have had a period every two weeks. Before that i was on the pill and everything was normal. I will wait to see what happens next month but if it does the same i will go to the docs.Why am i getting frequant periods?
when i stopped the pill, the same thing happened to me. it sucked! after 3 months i went to the dr. and she put me back on the pill, said it was my body adjusting to being off the pill and she had no idea how long it would take to regulate. i didn't feel like waiting it out.
that is actually normal i think some people who are teenagers have really irregular periods and they are supposed to level out when you get older i would talk to your doctor if you want to but i wouldnt worry about it that much because i learned that sometimes that happens to people