OPK question, TTC #2?

I've been trying to conceive on my own for 3 months now. I tried the CVS brand OPK this month. My period started on February 28th. I started the OPK on March 7th. I got [i thought] was a positive on March 11th, so the husband and I BD'd. Took it again Friday, March 12 [curiousity] and the result line was darker than the test line, so again the husband and I BD'd. Saturday March 13 took another one, don't ask why lol, and it was still positive. Needless to say the husband and I BD'd again. Sunday I took one and it was negative...So since I am showing a negative OPK have I ovulated? Did we BD the right days??