Implantation Bleeding?

I gave my birth control pills (Tri-nessa) the boot mid-pack last month. For reference, I've only been on the pill for about a year. On September 20th a got a regular period (the same flow I had before starting the pill). It lasted for about 5 days. I have had sex every day to every other day before and after my period. On October 3rd I started spotting brownish/pink. I'm still spotting as of today, pretty scanty, because it had disappeared for a day or two. Still having sex since then. I have never paid attention to ovulation dates, so I'm a little confused. Could this be implantation bleeding, ovulation bleeding, or a side effect from ditching the pill? Anything will help! Thanks! Xoxo