post partum

Hey ladies need some advice. Had my son 7 almost 8 weeks ago. Exclusively breastfed. I stopped bleeding around week 5

My husband and I were intimate for the first time since having baby on Saturday night last week 17-12-16 (we didn't use protection 😕) & today I have a small amount of brownish/pink blood when I wipe. Could it be from the sex or could it be implantation bleeding!😐

Need help!!!