Implantation bleeding? Period? Nothing?

Hey Everyone,

So made a post earlier, but realized I was off about my af.

Around Tuesday or Wednesday last week I started spotting. The thing was it was dark brown ( darker than I have seen before), so it was pretty unusual for me. First thing that comes to mind is implantation bleeding, but then out of nowhere bright red spotting comes. It’s mainly been dark brown, but the bright red throws me off. I’m confused. Also my af isn’t due to come until September 18th. Has this happened to anybody else before? Please help!?