Implantation or period?

So I'm trying to figure out if what I have is implantation blood or just a really short period. Boyfriend and I had sex 3 times this last month every time with a condom the first time was in the beginning of the month a day before my period started condom ripped and I bought a plan b the next day and took it. Each time after that we had protected sex. My period should of started on the second and I'm super regular and on the 5th I cramped just a little bit and then the next day I bled light regular flow it seemed like colors seemed normal a little bit more brown but normal the day after I put in a tampon happen to forget about it and it did not fill at all. Please tell me this is just a light period 😩