Brief Answer:
Hello, I would be happy to help you!
Detailed Answer:
One way that emergency
contraception works is to delay ovulation, but based on her cycle and the timing of the
unprotected intercourse, she had ovulated well before the time of actual intercourse. Even taking into account a 26 day cycle, she likely ovulated around 10/26th, well before 11/7th. So in this regard, based on the timing alone, conception was incredibly unlikely.
Given the timing of the pills, the most likely effect is that they delayed WHEN the lining would shed. Yes, most women experience some withdrawal bleeding that is like a period, but given when she took these pills, I think that it has just drawn out the latter half of her cycle.
Stress will not play a role in this case.
It will be hard to tell if the bleeding is related to the pills or her period - but I think that when she does start bleeding, assume it is her period.
The delay will likely be about one week (i.e. one week later than her usual expected period).
Once she gets her period, her cycles will likely resume a normal pattern.
She should take a test exactly 2 and 3 weeks after the unprotected episode. This would be on 11/21 and 11/28. If these are both negative, then she did NOT get pregnant from intercourse on 11/7.
I hope that this answered your questions - if you would like clarification, please let me know with a followup question!