I remember a similar distinct dream of mine. It didn't actually happen but the anticipation was intense.
It can depend on a literal connection to the conscious world - such as if you've experienced rape and how it's dealt with.
But I see it as an expression of your fear/rejection of something being forced on you against your will. Do you feel this is happening in your life? Is there something you're doing/been asked to do that you don't wholeheartedly agree with? Do you feel victimized?
And this could be something you are forcing Yourself to do that your Higher self doesn't agree with. Your heart's not really in it and doesn't agree.
With this dream subject, I think another clue is that the rape doesn't actually happen. This is good in the dream, I know, cause it's very scary. I think this is more symbolic that the dream is an emotional expression of fear/victimization/powerlessness or something along those lines......