After I turned 30 my periods changed so much. They were more painfull and more flow. Last year I had back to back periods and this freaked me out because just like you, I was very, very regular. Like clockwork. I had my period every two weeks twice in a row and had breast tenderness that lasted about 2 months. I went to see my Primary Doc and was referred to the OB/GYN. Turns out there was nothing wrong with me at all. I was stressed. I had lost my uncle to a horrible illness and having other health issues and a really hard time at work. All those factors together stressed my body out and I beleive that is why I became irregular.
I do think that you should see you Primary Doc about this because you really dont want to take any chances. I understand your concern. I have a female OB/GYN and there is always another nurse in the room as well. Please take care of you. Good luck.