If you were already late for your period by the time you slept with guy #2, it is not going to be guy #2's baby.
Here's what the conception calculator says for a due date of August 13 --
Possible dates of conception: November 10 to November 23, 2012
Due date: August 13, 2013 (40 weeks)
yeah she told me that my due date was going to be August 13th. And in the question i meant to put i started my period November 1st and ended November 6th.
Sounds to me that u were already pregnant before u slept with guy #2. If u slept with him on Dec6 Dec13 is too early to test. Implantation doesn't take place until day 8-10 of ur cycle. And then u would not get an accurate result until around day 14. Did the dr tell u your due date, that may help u better figure out who the father is as well. Hope this helps, good luck.