concerned!!!!

H
So was suppose to have my period june 16th, I had very light spotting when I wiped but that was all. We want to have a baby so have had unprotected sex. Took pregnancy test they came back negative. It is the end of the month and still haven't had my period. Could I still be pregnant even with negative test? Or what else could it be? 
Ps havent been stressed at all!