What a horrendous thing this perv did. I'm so sorry.
To me, that you were affected quite strongly by this pervert is totally valid and legitimate. At the same time you're kind of reprimanding yourself, 'why am I reacting like this, I know all the therapy principles, I should be able to handle this'. Hard to acknowledge though it is, you were a victim.
The truth is that keeping the experience in is a recipe for depression and ptsd to set in. However, that is not to say you have to embrace a victim identity. It's just so important to obtain compassion for the terrible experience for proper healing. At this point this should be like on the front burner. You know much more about who one can tell in order to get the proper support when revealing what happened. Not to be vulnerable to someone who will be indifferent or who starts giving advice.
This might address the roller coaster. lmn Here for you always