Do the thoughts and speculations that we have just before and after sleep often turn out to be true?

I've never really been able to 'prove' this idea, but I've often felt that the thoughts that I have just before and after I go to sleep seem quite clear and objective; it's as if I suddenly have access to all of the truths in my unconscious mind that I don't really want to know about and that I have been blocking from my mind. For example, I've tried to avoid thinking about all the possible mistakes that I've made in exams this year but today when I woke up I had thoughts of one of the mistakes I'd made and it wasn't even a mistake that I'd consciously avoided thinking about. I know that Freud believed something similar to this, but in your experience are the thoughts that we have just before and after sleep the truest and most insightful thoughts that we have?