Hi. I am 20 years and just recently had a baby 5 months ago. My period has been regular since about a month after she was born. Well I started my period on November 7, but it only lasted less than 24 hours. And I still haven't gotten it again. it usually lasts 5 or 6 days. I took a pregnancy test about 2 weeks ago but it was negative. What could this be? Could I be pregnant but it was just too soon to test? Thanks!