Confused about implantation

Hi ladies...might be TMI for some...

Just some information before I ask my question:

I got off the pill on Dec 20th (I took 2 of the first white pills on the 19th and 20th)

AF came (on the pill) from December 10th-16th and then my AF came AGAIN more bright red and heavier (off the pill) Dec 27-30th.

My cycles are always 28 days and usually last 7 days.

Anyway, today I experienced spotting. It was brown and it happened only in the morning. (Only on my underwear) I haven't had anything else. I BD during the holidays so I was wondering is this implantation bleeding or spotting from the pill?

Sorry if it's a stupid question but I'm a newbie.