My period is a week late but pregnancy test says I'm not pregnant

Mandy
So it's really weird I'm usually very regular on my period! I usually start in the 18 at the very latest the 19 when I'm a little more active that month. 
It is the 23rd and just took a clear blue test and it says not pregnant I took a first response and the like was very faint. 
What should I do? I still haven't received my period or even any sign of it coming either. Normally I have bloating and cramps the days leading up to it.