What could this be?

Melanie • Woman of God 🙏🏽 01/26/17 👧🏽💖 09/15/2020 👶🏽💙

Could this be implantation bleeding, start of a period, or maybe from sex? I have been trying to conceive after my miscarriage in August, and I didn’t get my period back till last month but as soon as I was off my period, I started TTC. I have constantly been having sex and last week I started having mild cramps on and off, my boobs have been a bit sore and tender but today like a hour or two after I had sex this bleeding started.