Ok, so it all started when i finished Elementary school. It was the grad dance and I really wanted to ask her to dance, but I was afraid... so i didn't ask her. Then for the whole summer vacation, I had dreams with her that involve me hugging her, talking to her, etc. Now, it's close to the first week of high school. I recently found out that she broke up with her last boyfriend, so she was single. I asked her if she liked me(after many days of asking), and she said yes, but not in a bf/gf type of way. So now all of a sudden, I don't those dreams anymore. I might have them like once a week, but its not as common as before. I really enjoyed the dreams, I wish the dreams would be similar to what would happen, because I still like her, but I'm afraid of what she'll think.
I think you probably have the dreams less often because you realize that it is less likely that things will turn out that way in waking life.
In a way you have accepted that nothing will happen so you don't have the dreams about her anymore. You might find on seeing her more as a friend.