pregnancy?

hi,

so i was on my period on the 17th dec - 21st dec.

ive been tracking my ovulation and everything. i was due on my period on 13th jan - 18th jan. i have no sign of my period at all. as i normal have really bad cramp a week prior, and ill start bleeding before hand. but no period has arrived at all... i did a pregnancy test yesterday night and it came back negative. so i’m not sure what’s happening.. any ideas?.

it also does run in my family (which is weird) that it doesn’t show until you’re past 12 weeks as it happened to me nan & auntie ect. was just wondering as i’m not sure what’s what at the moment :)