You're lucky. Sometimes I dream of a mathematical structure and it makes 100% sense in my dream, 0% sense in reality. Or I'll wake my self up by laughing hysterically and there was absolutely nothing funny about my dream. The feeling of something being valid, in a dream, seems to have nothing to do with reason, for me. Haha.
I do think we review things in our dreams. I remember being very little, and my stepmom wanted me to memorize the home telephone number... it was hard for me because of my age, and I could not even get the 3 first numbers down I don't think. I took a nap, and when I woke up, I had it completely memorized... I didn't understand how. Even now, sometimes when I dream, I'm almost having a discussion about something.