I had unprotected sex i tk postinor 2 after iam save

Hi,I need a help here,my girlfriend having her period on 31st august 2013 and end it on 4th September 2013. On 5th September,we had a protected sex and I EJACULATED INSIDE HER VAGINA BUT STILL IN THE CONDOM. For safety measure,she took postinor 2 but only A PILL,NOT TWO. On 9th September,WE had a protected sex again but this time I ejaculated OUTSIDE and she did not take postinor 2. On 10th September,she had a vaginal bleeding or maybe I could say period I'm not sure and the bleeding stop on 12th September. My questions are:

1) The bleeding is a sign of implantation bleeding or vaginal bleeding or a period?
2) Should both of us be worried whether she will get pregnant or not?
3) When she will get her next period if that bleeding is not a period?
4) Since when we should count her next cycle? On the day she end her period or the day she end the bleeding? Please reply me as soon as possible as I'm so worried of her.

Hi Anon,

If you took the pills as instructed, there is a higher chance they will protect you against pregnancy.  But you will need to wait until your period is due, to know if you are not pregnant.

Best,

Daisy