This is my second week on NuvaRing. First month was going fine fo...

This is my second week on NuvaRing. First month was going fine for a couple weeks. About the end of the second week, i started having BAD cramps. Which is completely not normal for me, ever. And so I asked my doctor and she said its normal. Ok, i can deal with that. When they continued throughout the third week, i got worried especially at night when the cramping would keep me up. I got headaches almost every evening, again, not normal for me. So I took it out and nothing. I waited two weeks without a period before it finally came. My period had been clock work since i was thirteen. Told my doctor, suggested i was pregnant? Took store bought test, said no. So, here came month two, same side affects except headache's. Week four now and no period still. Ring was taken out a week ago. Dont believe i am pregnant, we are always careful. And if i was pregnant, why would i have my period the first month (after two weeks)?