Implantation or early period?

La

Hey all, I’m not due AF for another two days and I’m usually on like clockwork. However tonight ive noticed a very small blob of dark coloured discharge in my knickers. When I wiped there was nothing. Is it too late to be implantation bleeding or do you think it could be the start of AF? Been having a lot of tingling sensation in my breasts but no soreness! Any advice would be appreciated