I can't speak from professional experience but I can definitely speak from my own.
I was about a month late with sporadic and wide spread periods even with birth control (nuvaring) and condoms. When it came time for my period I noticed an increased amount of cramping to the point where I kept thinking it had to come that day. I took a pregnancy test and there was no doubt about it, the line was so dark that it drew the ink from the other areas of the test.
My friend, however, is having issues trying to conceive and has this happen to her a good bit. She feels cramping, boobs get sore and tender, and she believes she sees a line on the pregnancy test when it is really her body tricking her.
The best thing you can do is either go to your physician's office and get a test done there or wait out the next 5 days.