What do you think the odds are?

My LMP was March 22nd but I ovulated on the 5th (day 28) , I used opk's, I had a BFN yesterday. I had a headache last night @ midnight , and as soon as it went away , one at 4am. I work midnights . As soon as I got up 430 I got another headache , and am feeling extremely queasy when I got up @ 230. Probably just AF , what do you think?