So confused?!?!

So this is my cycle this month. On the 21st I bleed really dark pink after sex or during couldn't tell. I put a tampon in over night n there was a tiny bit of brown. I also ovulated the 18th 2 days after my period n on the 21st?? On the 12 day of my period I started taking concieveeasy pills. Any explanations??? (Periods r irregular) thinking it could b my period getting regular, sti, ovulation bleeding, or implants bleeding. says Google.