help! implantation or out this cycle?

[YadairaD]

This is my 6th cycle ttc. I'm about 16 dpo (cd 33, AF is 3 days late) but I know I could have o'd a few days late. I checked my cm and it was pink and now it is almost like a very, very light period when I wipe. My periods are always heavy right out of the gate and stay that way, I've never experienced a light period. Today I was really irritable/moody, fatigued and nauseous. I'm hoping this stops by the morning. What could this be? The witch about to show or is light bleeding normal? Like I said, I've never had "spotting" so this is strange to me. If I did o late (which is entirely possible) Could this be implantation bleeding?
How long does implantation bleeding last?

Please help!! Thanks in advance

 

[Oasis717]

I'm sorry I've never had implantation bleeding only implantation cramps (with my youngest) but it def can show up around the time AF is due, it takes a few days after implantation for the hcg to build up high enough for a pos test, good luck! Xx