Implantation bleeding??

Hey guys so i recently posted freaking out about being late for my period. So my period was supposed to arrive on 1/11 and this morning (1/14) I woke up to somewhat heavy bleeding which seemed like its normal red color on the first wipe & then a little brown on the second I guess bc it was lighter than I thought? Anyway throughout the day I had a couple tampons in which seemed to have been filled up with a regular shade of red. But I’m about to take a shower and I went to wipe after peeing and now I’m seeing this which seems a little lighter than before, but not necessarily pink or brown. Do you guys think this is implantation bleeding? Could I even have implantation bleeding 3 days after I’m supposed to have gotten my period? I thought implantation was usually before? I took a pregnancy test on the 11th when I was supposed to get my period (too soon I know) and it was negative. Was planning on taking another later this week to be sure. SOS & sorry for the tmi