Forgiveness doesn't have to mean allowing someone back in your life. Forgiveness is a heart issue. Forgiveness is about you. Trust is about the other person. Forgive the friend, but decide whether you can and want to trust them again.
Resentment eats you up like cancer, forgiveness brings relief. Forgiveness doesn't mean you forget the wrong, because the scar remains, but the scars are a reminder of your maturity, choosing not to treat someone else the same way.
Chances are she doesn't know that she's hurt you. What you now see as intrusion, she does not. It's not fair to blame her for her ignorance, 100%, if she's not aware of the problem. Also, one slip-up does not necessarily deserve banishment. Wariness, discretion & caution, maybe - but not turning your back. However, if it's a constant stream of deceitful, hurtful issues, then yes, sometimes you must walk away to keep your sanity.
Forgiveness is divine. If you wait and never say or do anything you might live to regret it. Also how can one know how you are feeling if you do not tell them? Let your pride slide. I know pride. Once in awhile ignore it. My opinion.