Ugh..what’s happening here?

Hi, everyone! I’m not really sure where to post this, so please be patient with me.

Last month, I had unprotected sex with my fiancée the day before ovulation. I’ve since taken about 6 tests..3 of those blue dye with the lines all the same, I’ll post a picture below. I took 3 pink dyes, two of those clearly negative, and one this morning with fmu that was a faint positive within the time frame, but the line went away after the 5 minute mark!! My period is due today, but so far, nothing.

Help me out here, ladies. Has this ever happened to anyone? I intend to continue testing to see if the line darkens, just looking for opinions until then.