can i trust this HPT?

[moodly.livejournal.com]

Relevant background info:
-- stopped taking Yaz approx. three months ago. In the last two months, my periods have been pretty much on time (one day delay max).
--use condoms for protection now, no accidents that I know of.
--I traveled via airplane last week (on the day my period was due) and I am also supposed to take another airplane trip on Thursday.

My period was due last Friday. It is still not here, and I took a test (First Response) yesterday evening. It came up negative. Today, still no period. Do I feel like I am premenstrual? Kind of, I feel a bit fatigued and headache-y, but have felt that way since Friday (at least) and the symptoms for my periods have always seemed eerily like the symptoms for pregnancy, according to my google knowledge.

So, can I trust the home pregnancy test I took?
Could my period possibly be delayed due to travel or getting off of HBC three months ago, even though my period has been fairly regular since?

Thanks in advance for your help.