Implantation bleeding?

Savannah
I am SO confused. So last night I thought my period started. It was 12 days past what I think was ovulation. It was a pinkish color with some Brown. I thought, oh well maybe next month and moved on. Well, it never came back. Today my boobs are killing me which never happens on my period. None of my friends have experienced this before so I figured I'd ask on here. Thoughts? We've only been trying for a couple if months so I'm not feeling desperate yet, I'm just really confused. Tests have all been negative.