Very early, short and very heavy period? but having signs of pregnancy?

my husband and i aren't trying to get pregnant but aren't preventing it either because we do want more kids. my period is always regular, comes on time and always 5 days. i started my period last week and it was 8 days early w/ 2 days of very heavy bleeding and it was done. i am having symptoms of very sensitive teeth to pretty much anything, migranes, little bit of nausea if i dont eat right when i get up and sore breasts. i took a pregnancy test about a week and a half ago after the symptoms started and it was negative. any thoughts??