I have literally just been through this lol. I was 8 days late (I've never been more then a day late), sore boobs, niggly headaches, symptoms that I had with my first pregnancy. Took a test when I was a week late and it was negative! Not even a hint of a second line. Went to the doctors, got a blood test and then the next day, AF arrived lol. So it was a 37 day cycle, which is crazy for me!
So I suggest going to your doctor and seeing if you can get a blood test, because that's 100% going to say if you are or aren't pregnant. Good luck!