I had a 1 night stand in the end of nov you had your pd in dec and even took a preg testit was neg then on Jan 17 i took a test it was neg then on the 23 and it was pos its not the 1 night stands righ?

Well yes you would be pregnant from the one night stand - if you had not had sex between then and when you discovered you were pregnant. Also it is not unusual to continue have your period whilst pregnant. Why you did not use contraception I do not know.One time is enough to get you pregnant - stupid really really stupid.