THE FIRST DAY OF MY LAST PERIOD WAS NOV 17 (TALKING ABOUT 2010). MY 8 WEEK ULTRASOUND PUT ME AT 8 WEEKS PREGNANT AT EXACTLY NOV 17. MY 8 WEEK ULTRASOUND WAS ON JAN 11TH, 2011 AND IT SAID I WAS 8 WEEKS PREGNANT PUTTING ME EXACTLY AT THE FIRST DAY OF MY LAST PERIOD OF NOV 17. THIS MAKING CONCEPTION AROUND DEC 1ST OR SO 2010. I WAS ONLY WITH ONE PERSON DURING THAT TIME HOWEVER, I WAS WITH SOMEONE ELSE ON OCTOBER 3RD 2010. GOT MY PERIOD 2 TIMES AFTER BEING WITH THAT PERSON. SHOULD I BE WORRIED THAT MY CHILD COULD BE FROM THE PERSON I WAS WITH IN EARLY OCTOBER WHEN I GOT MY PERIOD 2 TIMES AFTER THAT AND MY CONCEPTION DATE WAS AROUND DEC 1ST.