i had unprotected sex in July. I did an HPT in early Aug and it said negative. a couple days later i started my period and it was a little shorter than usual. In september, i went to my gyno for my annual. all my tests came back normal and i had some spotting a coupeld days after and then again, had a shorter period. Now it is october and i am spotting again and i took another HPT 3 days ago. Do HPT still work 2 months after sex?