Beginning online poker

[dachord]

So I finally made the decision to play online poker. At the suggestion of a friend I logged onto Poker Stars and first started with the free money games. After getting used to the play of online versus live play, I entered a $10 buy in. There were 1234 players and the payout started at 135th place with the winner getting a little over 2G. My game plan was to play supertight until I was in the money. The strategy was working fairly well, although my chip stack stayed a little below average (which is what I expected). I was at a table where my stack was about average with the other 8 players when all of a sudden I was moved to another table. I'm not sure why I was moved as nothing had happened at the table of significance. Now I found myself on a table where the other players had chip stacks 3-5 times my stack. The blinds were now 200/400 with 50 ante. Needless to say, I was soon pushed out and finished the tourney in 173rd place. My question concerns being moved from a table where I was relatively equal to the other players (via chip stack) to a table where I was at a sizeable disadvantage. Is this normal or is there something else going on that I am naive about?