I took a first response pregnancy test and its negative, but I'm 12 days late when I've never been late once in my life! I'm under noo stress and I'm healthy, any adviece?? Please?

I have had problems like this before. One thing could be that you are hanging out with different girls a lot more and in all my cases I just ended up getting on there period cycle. Go get a blood test done they are the most accurate. When I was 16 or so My periods went out of whack and one month I would have it two times then the next month I wouldn't have it at all and it was like that. And before that happen I was never ever late ever. So I know it may be scary but some times you can be lucky:) I hope I helped a little:)