implantation bleeding or?

on tuesday i started spotting for the first time ever and i have been on the pill for a year and a half. i finish my pack today and my withdrawal bleed should start next mon/tues. i have also been having a slight cramping feeling. i last had sex on the 1st september and used a condom in addition to the pill (condom did not break or leak or anything) i have also had a withdrawal bleed since then. could i have been experiencing implantation bleeding? i was on a course of flucanozole the week before the sex but i had taken six active pills between finishing the tabs and having sex.