I love this girl... What do I do?

Well... We are dating and I love her... She created a fake email last night and started saying she was an ex of hers and started trying to say that she may be cheating on me as the supposed ex in order to test me I believe... I am considering breaking up with her over it seeing as the whole ordeal caused me to go into a panic attack due to me eve remotely considering losing her in that kind of situation... I was shaking constantly and I had to leave the room in order to not cause a scene... I haven't slept since then... Am I being unreasonable by wanting to break up?