After some advice ......

Ok so abit of background .... I have irregular periods, from 28-32 day cycles, I'm 15dpo, af was due yesterday and nothing, all I had was cm. this morning no af just cm again, about 2hrs ago I went to the bathroom and had a pink show mixed with cm, my usual af lasts for 4 days and I never get a pink show first, it's usually bring red straight away and medium to heavy flow. I don't even need to wear a pad with this amount so I'm really confused as to if it's a very strange af ( which I've never had ) or late implantation bleed?! Any advice would be greatly appreciated xx