If you don't feel comfortable chilling with the person or things aren't the same anymore. Just leave it for a bit. Go on a break. If the behaviour still persists, then you know it's time to leave. You don't have to be friends just to keep the person happy. You define your world and you choose your friends. If they are making you feel like that, then maybe you should ask yourself if she truly is your friend? As much as you don't want to ruin a friendship, and all those good memories etc, sometimes you have to.

Ask yourself this, if she was the only friend you could ever have, would you rather choose her friendship ,or reject her and be alone.