I had my period 24/12, had intercourse once after that then period again 18/01, it came when due so I didn’t think anything was weird until now, I haven’t had intercourse since time mentioned above. I was due for my period 3 days ago and it hasn’t shown up yet. Could I have mistaken that second period for implantation bleeding although it lasted 4 days and had my pads full like a regular period, or is my body just a bit off and could possibly just be a late period?