I had unprotected sex 3 days ago. The day after I noticed I had odorless, cottage cheese like discharge with a little bit of itchiness at the vaginal opening, but that went away; However, for 2 days now i ve been spotting..brownish stringy discharge when I wipe, and now see blood particles floating around in my urine . what could this be? implantation bleeding? yeast infection? an STD?