Help please!! What is going on??

Af was due yesterday well around 330 this morning I was just getting home with the family from a long 6 1/2 hour drive home from Florida and this yucky dark brownish stuff is on the tp when I wipe now I have very heavy bleeding and this is very light I have a pad on and there is only one spot no cramps like I get I don't feel yucky like I do when af is here just tired a little but I'm guessing that's from the trip. Can anyone tell me what this is or could be??