Is it too late for implantation bleeding?

I am currently 13 day's late for AF! Yesterday I noticed I had spotted a light/peachy coloured blood when going to the toilet but only once. No spotting today as of yet but I have been having mild cramps. I have been testing every day since AF was late but I didn't test yesterday or today (ran out of pregnancy tests) my boobs are a little sensitive and I have been having mild. Cramps. Does anyone have any experience with this? I had the implant removed in October so my periods are out of whack anyway.