What is going on??

I'm so confused. My husband and I have tried so hard this month, every day during fertile window, and never more than 2 days without sex the rest of the month. This morning I am 7 dpo and AF is still not due for another 8 days. (I generally have longer cycles). Well I got up this morning and there was a little blood on my underwear. I went to the bathroom and it started dripping out of me. And it was dark red. Is there any way this is implantation bleeding and not AF? I thought for sure this was the month. I need some kind of hope!