Is it possible that implantation bleeding can happen 16 days after last day of my period?

I have been TTC for 2 years! I was on Provera last month to help stimulate my period. Due to not getting it for 4 months. I do not want to get excited, but it has been a solid 2.5 weeks since the last day of my last period and have not bled since. Today I just went to the bathroom and started lightly spotting?! What’s happening?! We have had sex with preseed literally before during and after my period so I mean it is possible. I have also been taking Pregnitude daily as well for a month, but idk implantation?