Okay, so I recently took out my Mirena birth control about the end of march and I switched to the patch. I got my period while I was on the second patch and I had it for about 2 weeks and I kept using the patch as normal. I put my first patch on for the new month the day before I ended my period and continued to change it every week. The fourth week (last Saturday) I took it off and I still haven't started my period and I'm supposed to put my patch on tomorrow! Could I be pregnant? Or could it just be because I changed birth control? I took a pregnancy test on Wednesday but it came out negative, so I'm not sure whats going on?