Implantation?

Emily

So I am due for AF in 4 days according to glow and ovia. I normally have a cycle of 28-30 days. I'm on CD 29 and this happened today at work. I thought it might be AF, but I came home and there's not much more blood. I just put a tampon in to check my flow.. Could this be implantation, or is it too close to my period TIA ladies!