Need some help.

mommabear
Hey girls, so I had sex on 2/7 & 2/14. My period was due on 2/24, and today would've made 4 days late until i woke up this morning with some bleeding. I thought it was af until I realized it was on and off. it's light pink when it's there and barely takes up a full wipe. 
I have a very uncomfortable feeling in my uterus, it feels like I have to pee really badly (even though I've been to the bathroom every 20-30 minutes and barely anything comes out). it's beneath my belly button and I just don't know what to think. My periods are regular and being 3 days late has never happened to me before. 
should I wait and see if it stops and count this as implantation bleeding or go ahead and count this as af?