Confusion advise please ?

I need a lil bit of advise. Now I'm not quite sure when my last period was but I roughly want to estimate around September 16-19 possibly. I can't remember the first time me an my partner had sex without a condom because he forgot it, didn't think anything of it, I wanna guess this happened the end of September an in November I spotted really lightly for three to four days and spotted just a hair bit more one day and the next day it stopped . This happened November 27-31. My periods are normally really heavy, if that wasn't my period could that of been implantation bleeding ?