Implantation question

Is it possiable to implant at 16 dpo? I ovulatednonc cd 14...I was 4 days late cramped the whole week started bleeding but nothing like normal I usually have alot of clots and cramps so bad I can't get off couch.But mild cramping period lasted a day and a half..I tested sunday when bleeding had stoped on a walmart cheapie it was bfn..I still having sore breast very hungry and mild cramping again..I know I'm prob crazy.Anyone have experince with implanting late?