Missed period.

My last period started October 26 and was done the 30. I haven't got my period yet and its now December 1. I took a pregnancy test November 28 (two days after missed period) and it came back negative. I've been looking up certain things about missed periods and false test results. Not sure if y'all had any other incite. I'm buying another test tomorrow and taking it just to be safe. If it comes back negative again I'm gonna schedule appt with my doctor. I've kinda been stressed the past week or so because of family problems, and now having a missed period. I was on birth control, but quit taking it because I lost my insurance, that was about three months ago, my period has been regular since then until now. Just wanted a couple ideas. Thanks all in advance! 17 & really don't want a baby right now.