Birth control and condoms

I think my body is finally getting used to my birth control and becoming regular. My boyfriend and I always use a condom and he pulls out before finishing and I’m on the pill. For the last few months my period has been really off. Would show up in the middle of the pack or not show up at all. I finally got what I think is my period during my placebo week but it was really brown and lasted about 3 and 1/2 days. Is that normal? Or could that have been implantation bleeding. Like I said we also always use a condom and I have never experienced one actually breaking but I’m still paranoid about a small leak that we didn’t notice that could have gotten precum inside of me. What do y’all think. Was that my period???