Could I be pregnant?

Ok so I'm freakin out... took Plan B a few days before the 15th of January bc the condom broke and then the condom broke again on the 15th meaning i could be pregnant... I have taken Plan B twice now in the span of two months so it's screwing with my system so maybe that's why I'm late... but anyways I had spotting about a week after taking Plan B and I thought it was my period but idk... I still don't have my period so I took a digital First Response test today and it was negative. Is there still a chance I'm pregnant?? Where the heck is my period??