TMI-what could it be?

I'm 5DPO today, AF due 12/2.  Last night hubby and I made love.  I went to the restroom afterwards and when I wiped I saw a little bit of red blood, not pink or brown but more fresh looking.  Things did heat up and get kind of rough while we were doing the deed and I did feel a little bit of friction towards the end.  Is it possible I just irritated the skin to that point or could it be something more serious?  From everything I've read in the past it's too early and the wrong color for implantation bleeding.