SHORTER PERIOD or implantation Bleeding

Kia
So AF wasn't due until 2/13 but showed up 2/10 and was gone by the end of 2/12 ... I usually have 5-6 days periods but this is odd that this month it was early and only two days long! I've taken two pregnancy test both negative !! Just wondering if anyone else had this happen since they've been TTC ... And if so does shorter periods affect fertility by any chance bc if not I'm hoping my period stays at 2 days it's wonderful lol