I started my periods between 12-13 and have regular periods of 4 weeks until about 2 months ago and now they are every 2 weeks also my breasts are tender and i have sore pains in my stomach, the doctor believes the pains in my stomach is due to gallstones but that does not explain why my periods are every 2 weeks. I came off the pill around 3 months ago so I wouldnt think that could be it. I am really worried about what it could be. I have seen the doctor 2 times and she says not to worry and it will pass but it hasnt. PLEASE HELP