I am going to go against the flow here and say that I think that it is highly unlikely that she did not see your e-mail. It is 2017, give me a break. I don't know the protocol of the "correct" method of disclosure in therapy, but to me it is damn cold that she treated you so indifferently and dismissively. Even if there is some "rule", which is ******** if you are not even aware of it, she was derelict in consciously avoiding your confession and destroying whatever presumption of trust you may have been developing. My courageous self would be furious and confront her. But, at the least, please start looking elsewhere. You deserve validation and someone who is willing to work for your trust.