No period :) can it be?

Aracely • Mommy of 1 waiting on BBy #2
So lasted the entire month of March with no period ... No signs of it only been feeling nauseous throughout the day and cervix remains the same... I've also been more tired lately :/ I have constant headaches... WHAT IS WRONG WITH ME??? I've taken pregnancy test twice AND THEY HAVE BEEN NEGATIVE :/