I was supposed to get my period around December 27 and January 27, but both were missed. I've taken 3 pregnancy tests so far, the last one was sometime last week--and they've all read negative.
I wasn't too worried about the first month that I missed it because my eating/exercise/stress had fluctuated somewhat over December. As well I've had a little irregularity since I took Plan B back in October (in November I was expecting my period on the 20th and it came on the 27th.)
I'm getting worried that there's something wrong with my reproductive system if I'm not pregnant.