I had sex with my boyfriend on Sept. 1. We didn't use a condom but he pulled out. Just to be sure I took a plan b pill. two weeks later I got my period on time. It was normal just like my other periods. Now it's Nov 2 and I havn't gotten my period since. I went to the doctor about a week ago for a UTI and they gave me a pregnancy test. They didn't say anything about it so I just took it as the test came back negative. but still no period. Should I be worried? or can the plan b pill cause this?