Sporting 4 DPO?

I'm having really bright red spotting, very light bleeding only when I wipe (sorry for the tmi!) but I'm fairly sure (positive LH peak) that I'm about 4 DPO. It seems too early to be implantation (and bright red?) and too late to be ovulating and feels like it wouldn't be low progesterone yet either... anyone have any ideas? We haven't had sex since ovulation so it's not irritation or something. I'm stumped! Any ideas? Thanks in advance.