period or implantation

I've been exclusively breastfeeding my son for 18 going on 19 months now and last month we decided it was time to try for our last baby (fingers crossed for a girl) so about 4 weeks ago I stopped taking BC and have been taking opks to look for lh surge with no luck and I have yet to get my period back from after having my love so yesterday we dtd and last night I was having cramps and pink spotting I thought my period was finally coming but there is nothing today and sex wasn't rough or anything so what could it be?

pic of my two boys for attention 😍