A similar thing recently happened to me. I thought I had to talk to T about it (the thing I was trying to tell her.) because I couldn't stop thinking about it. I thought that maybe if I talked about it, it would get off my mind. I got very close to telling her about it, but then made justifications and rationalizations to myself, about it, and decided I didn't need OR want to talk about it, and we haven't discussed it since.
Maybe you need to talk about your shame, rather than the thing itself. Gentle hugs, if you want them.