6 days late - positive or negative?!

So weird, I had unprotected sex 5 days before my period and I am very regular every month. This should have meant that ovulation was already over....

I tested when I was 1 day late. It was negative. I retested on cheap tests (CVS brand) and there was no reading. No lines. Nothing. But I did pick it back up after 5 hours and one of them had two faint lines for a positive. I retested this morning with the last CVS test and got this...looks negative. What do you think?