Help!

I was intimate with my boyfriend on the second day of my period last cycle. We grinded and such. But didnt have sex. I had a positive ovulation test cycle day 15 and now am on cycle day 27 (12days after positive ovulation test) and i got a small tiny tiny bit of blood when i put toilet paper up there. Could it be implantation bleeding even though i grinded 25 days ago.? I had a negative pregnancy test this morning. Is it possible it could be implantation even though i was intimate cd2 and its now cd27!? And most people dont get ib?