Help!!!!

So my boyfriend and I have been TTC for a few months now. But this past month we have gotten more serious about it, I've started to take Geritol everyday and still take my metformin. I ovulated last week, glow said my best chance to conceive was on Wednesday. I'm due for my period on October 8. But today I started to bleed, its dark brown. My period usually never starts off brown, nor does it start early.

Could it be implantation or just an early pregnant??