Was it over confidence or was it just variance? Do you think the decisions and plays you were making were good?

You should post some hands that you started losing and get some feedback as to whether or not they were still good plays. The worst thing in poker I think is letting variance over a short time frame (one tourney, 1 month of tourneys) dictate your play cause that can lead to much longer term mistakes.

This works both ways - keep doing bad things cause they are working or stop doing good things cause they aren't.