I would like to know if I had implantation bleeding. I satrted my monthly on Jan. 2 ended on jan 6. Started brown spotting on jan 8th, which is 2 days after I ended my monthly.
And if it is not implantation bleeding, then does implantation bleeding only happen when you ovalate?

This is not implantation bleeding.

Implantation bleeding (very rare, btw) is approx. 7 - 10 days past ovulation. Ovulation "typically" occurs 12 - 16 days after your period.

Your spotting was likely just part of your period.