Erasing Dream From My Brain...First Experience

Have you ever trie erasing your dream from your brain, your memory. Today I witnessed it for the first time. My memory is very bad, in the sense I remember almost everything that goes through my mind, whether its a thought or a dream. Last night, I had a dream. After the dream was over, I woke up little. But I was not completely awakened. I realized that the dream had something painful, it had to do with death of my sister. So, I decided subconsiously to erase that dream from my memory. During that subconsious situation I started diverting my brain to a completely different thoughts, I started thinking something that had nothing to do with that dream. After sometimes, my subconsious situation went into totally unconsious situation, i.e. I slept. After my sleep was over and I woke up, I realized that the dream I had was completely erased from my memory. The only thing I remember is that it was painful, and was worth erasing from my brain.