Implantation bleeding or plan b?

I took plan b Tuesday of this week. Monday night is when the incident happened and I took plan b early on Tuesday morning so within 14 hours for sure.

I was due for my period yesterday. Yesterday I started to having spotting which was brown. I let it go. Sometimes I do that before periods. Then this morning it was full on period ( I thought ) I bled through my shorts. So I change and get cleaned up and put a tampon in. And ever since then I’ve barely bled. And now when I wipe it’s pink but very light.

I’m hoping this is just spotting due to the side effects.