Implantation bleeding or light period???

I’m spotting I’ve never spotted before I’m going on day 2 of spotting which is supposed be be day 2 of my period. I always start on time down to the hour but this time I started on time but it was supper light and hasn’t changed. Usually I’m bleeding enough to fill a pad in half an hour but this time i’m not filling my pad at all. So I thought to was implementation bleeding but I took two test and they came up negative. I googled it and it says if I’m having implications bleeding i need to wait a few days after it stops to test because I don’t have anything of the hormones yet. I forgot to take a pill one day and had sex around the time of my oblation.