Definitely tell her. You don't have to feel badly; just apologize for not telling her sooner and for trying to keep it a secret. Be honest about the fact that you didn't follow the contract and didn't want to talk about it with her then, but let her know how intense it has gotten and how much you DO need to talk about it with her now. She wants to help you through your struggles and get you to a place of peace where you don't resort to SI, and I am sure that she won't be mad at you. She may have wanted to know sooner, but I am sure she knows that it isn't easy to talk about it and will be proud that you are brave enough to tell her the truth and want help for it now. You are so strong and will get better, and your therapist will definitely help you through it. Stay strong and let me know how it goes, love!