My normal period date is on 3rd-5th of month. I had been intimate with my boyfriend on 14th of this april without penetration but with touching his penis on the surface of vagina.. Took ipill just after 4 hours to be really sure. Now after 10 days on 24th apr I am experiencing brown bleeding with cramps ,sometimes red blood also.. I took HPT on the very day n got negative. I am freaked out if I m pregnant as according to other forums it could be implantation bleeding.. Please tell me if it is implantation or withdrawal bleeding? How do I be sure which kind of bleeding it is? How to know the difference