Implantation bleeding?

Last night I noticed I had some type of spotting. It was SUPER light (if spotting could spot, that would've been it) so I didn't really think anything of it. This morning, I noticed it was a tiny bit heavier and it doesn't look like AF spotting. It's darker in color, and brownish? I didn't notice ANY of this kind of stuff with my first child, and we are actively TTC. My friend was the one who mentioned implantation bleeding. AF is due 9/7, and I'm praying she doesn't show!