I have been on the same birth control for almost 4 years now. My period has always been regular and I've never been late or had a scare that I recall. I started my last week of pills (the placebos) Sunday just as always, and I usually start my period no later than Tuesday. I usually start Monday morning actually. I am always cramping and my back is hurting Monday morning even if I don't start until Tuesday. However this week I have no started and I have not cramped, bloated, had back pain, or any of the usual symptoms that I am about to start. I got worried and took a pregnancy test last night and then another today at lunch time. They both came out negative. Does anyone have a clue what might be going on? And also I am supposed to start my new pack Sunday, do I need to hold off just in case I am pregnant? Any advice is appreciated. Thanks!