Her cycle starts on 25th Jan and ends on 31st Jan and you had made sex on 5th Feb ie.on 12th day.
If her period is regular,then you have sex in unsafe period.
So she should be take one Emergency Pill like I-PILL or UNWANTED 72 as soon as possible and must be within 72 hrs.
A little spotting may occur with abdominal pain
So dont worry and have to wait for next period.
All the best.