Could this be I'mplantation bleeding!

So me and my partner had sex on Wednesday (my most fertile day), and this morning I wiped and had some light pinkish blood.. It's got a bit heavier so I've put a small tampon in and the blood is darker now. I'm experiencing some lower abdominal cramps but they're not bothering me that much. Could I be experiencing I'mplantation? (I only just finished my period on Tuesday btw?!) Has anyone else had this? Please help!!