Need help: declutter my mind

Please help me. I feel like a stupid monkey with my mind wandering around all the time.

At first, curiosity helped me a lot, since I'm currently pursuing a grad school. Wandering around helped me in finding relevant literature for my research. It also pointed me to keep looking for newness and rigor in my research work. Curiosity and oceanic sense of wonder seems like a perfect combination at that time.

But nowadays, I must admit that I find it difficult to control my curiosity and to keep focus on what is important in my current life. Everything suddenly add up and become too much. I feel overwhelmed, panic, stressful, and usually end up doing and accomplish nothing. When my mind wanders around, my overall performance suffers a lot.

When I'm searching for an academic article, for example, I end up with 50+ articles and usually don't have time to read (or even skim) all of them. I probably only need 2 or 3 articles, but I don't know how to resist the temptation of downloading more and more articles. (The same goes with mp3, books, magazines, movies, etc.)

Every night I lay down, my mind starts wandering around to tons of different things and it keeps me awake. Every time I online, my browser opened more than 20 tabs at the same time. It seriously drives me crazy.

Sometimes I feel like I just want to throw away the stuff I owned and format my 1 TB external HDD (that full of stuff). I have a guitar that I bought 2 years ago but only being played 5 times or so. I have a lot of books and novels that I never finished reading. I have a couple of clothes that I bought but never used.

Here is my priority for 2013: (1) finish my thesis, and get a degree (2) writing a fiction (3) regain physical health (4) marry my girlfriend, am I asking too much here?

Sorry if I was a little wordy, English isn't my first language. But I hope you understand what I'm saying and can help me.

Much appreciated.