I have been told that I dont understand odds

I have been participating in a random drawing where every week one person out of about 2000 is chosen as the winner .
I assume that the first week , my odds of winning are one in 2000.
Easy enough right ?
But if I compete two weeks in a row with the same one in two thousand chance, is not my odds of winning one in one thousand since I done it twice?
If I play every week for a whole year are not my odds about one in thirty eight?
My coworkers are saying im retarded