Is there an explanation for a winning streak?

Scientific or otherwise? I had just been thinking of one year in my life. I won a New Year's Eve weekend package for two, an all-inclusive vacation package to Las Vegas for two, a drawing for $500, a promo from Dr Pepper for a skate board, $1,500 cash from a radio station, a music gift basket (CDs, concert tickets, etc), $5,000 from the lottery, and various scratch off tickets from the lottery. All in about 18 months. It was so much that friends were asking me to play the lottery for them, and I ended up giving some of the prizes away because I felt it was unfair that I had won so much.

Since then, I still buy raffle tickets from kids and put my name in for drawings here and there, but the most I have won was a weekend at a water park. I'm not complaining! I am very fortunate and don't need prizes though I like to win.

I am not the only one who has had winning streaks. What causes them or are they really just random? At the time of my streak, I had just graduated college and didn't have much money.