I have been having my period every 2 weeks for the past 2 months. I had my yearly check up in march and everything was just fine. The last part of April my BC pills were changed. I had been taking the same kind for like 3 1/2 years. Could that change have thrown my body out of wack and if so how long will this take to get back to normal? I called my doc and they gave me a different pill and said it may help cause my body may be "rejecting" the other kind.