It was a Saturday night, many years ago, and I was a college student sleeping deeply. I saw in front of me a quiz with my name on it, and a hand wrote a grade on it in red pencil. There was nothing special about the quiz and nothing special about the grade, which I saw was a C+. The next week I was in that class and I knew that those papers would be given back to us, and I had this urge to tell the instructor about the dream and that I knew what the grade would be. But I imagined if I did that the grade would be wrong and he would think I was a nut, so I didn't. Right after this the quiz came back and there was a big bold C+ on it, just exactly like I dreamed. It made a big impression on me, and after this I had other dreams which also came true. Some seem of no importance and others seem to be very important. Now, I still get them sometimes but I take them seriously now.
You may have had an idea (even if only unconsciously) that you were going to get a grade around a C+ on the quiz. I've found that when I've taken an exam, I can usually tell what grade I'm going to get before I get the exam back, based on how many of the answers I'm positive about.