I took the morning after will 3 days ago, now I've had whiteish discharge and stomach cramps and lower back pain, is this normal?

It could be... often you will experience some irregular bleeding as well. While emergency contraceptive pills work well at preventing a pregnancy, they, like any other form of birth control, are not always 100% effective. How soon after the unprotected sex did you take it?

If you continue to have symptoms, you should check with your doctor.