I thought i wasn't pregnant?

i thought i was maybe preg. but there was only a very very small chance. after two weeks of stressing i got my regular period. it was on the right day and i'm sure it was normal. really heavy for 3 days, lighter the 4th day, and brown spotting for the last day or two. exactly the same as always. so i figured i wasn't pregnant. but now i am a day late and i don't know why. i have not been stressed.. i don't even feel like it's coming even though normally i get terrible cramps right when it comes. i haven't done anything since my last period to get myself pregnant.so my question is, is there anyway i still could be even though i've had a regular period? i haven't shown any signs at all except being a little emotional which (i think) is pms.... someone help me out? anything would help..