Possibly pregnant?

I have been having sex every single day up until my period was due December 5, still no signs. My nipples have been hard, extremely sore, and very red and one of them is kind of purple. I have pretty mild cramps, but no bleeding or any other signs of my period coming. I have tested 3 days late, 7 days late & now I'm 12 days late. Should I test again now or should I wait until next week? Is there any reason as to why my period would be so irregular all of a sudden? Any advice helps!