Most Helpful Girl
Don't answer. If she doesn't leave you alone call the police.
Most Helpful Guy
You should find a new girlfriend. This shows a lack of respect for you and a very one-sided view of relationships. Imagine how she would have reacted if you had slapped her! This is your sign; RUN!
The problem is not how much the slap hurt. The problem is that if she thought it was okay to do this, she will think it is okay to do other things that show a lack of respect for you and you will be in a one-sided relationship. It doesn't matter that you feel strong enough to tolerate this behavior; you shouldn't tolerate it.