is it possible to have negative result even your pregnant?

my peroid was late by 17 days but the result of my pregnancy test was all negative.. (a total of 4 test and yesterday is my latest test) im still waiting for my period to come, but also expecting my pregnancy. i know its too early to assume that im preggy, but what i need to expect by this? my period was late, i frequently need to pee, my breast is getting bigger, but no morning sickness..