The first sad moment in Hong Kong

Hong Kong is really an exciting place; however, I have been sad these days,"no-name sadness" in Chinese.
It began in this Monday where I finished that long, long meeting. I tired up all my strength for preparing it. Then I collapsed. I slept more than usual, I ate more than usual, but neither of them solve the problem. I got into a disease which I can't cure myself. So I did everything orginally came to my mind, which is not my usual way. The sadness remains.
I couldn't get to asleep yesterday. It is the first time. I thought a lot about my study, my family, and a lot of other things. I can't work out any of them. Then I wake up at 6am, 7am, 8am, and finally get out of the bed at 9am. I am confusing by my dream and my real life. I can't tell which one is true and which one I prefer.
I know I will finally get over it, but I don't know how. I lost everything.