9 dpo is this AF coming or implantation *tmi

Melyssa

So I took a opk February 13 it was very very positive which means I would have ovulated around 14th or so, BD 13th, 14th, and 15th. This afternoon I was having pretty intense cramping/pinching sensation like it was VERY noticeable. I went to the bathroom after about 15 minutes of this pain/sensation and had brown spotting. The pain has since stopped and so has the brown discharge. Is this implantation?!?