Period but pregnant?

B
I know this is a stupid question, but I'm just grasping at any possible hope I'm not out this month. I am scheduled for AF to come on July 6. I am always on time - to the time even. 
I surprisingly started bleeding this past Friday, June 30, which technically would have likely been the implantation day. I bleed normal. Full tampons ever six hours or so. I stopped bleeding Monday - so four days. Is there any chance I could somehow be pregnant? I'm nauseous, tired and have wicked heartburn. I know I'm probably out, but is there any hope?