Hello
THanks for writing to us with your health concern.
THe 
emergency contraceptive pill generally induces withdrawal bleeding in most women.
This can occur a few days after intake, and might not happen at all.
ALso, the ECP ( emergency contraceptive pill ) has a side effect of messing up with your normal menstrual cycle.
It can prepone or postpone  your expected period by a week or more, upto 7 to 10 days.
Hence, the delay in periods is most probably due to the ECp that you have taken.
With no ejaculation inside , chances of 
pregnancy are quite low
Further when taken within 120 hours of unprotected sex, ECP is more than 80 % effective in safeguarding against pregnancy.
So chances of her being pregnant are very low.
However still it is best to take a pregnancy test 4 weeks after unprotected sex, to be on the safer side.
All the best
Take care.