Practice results and trends

I'm feeling demoralised. I started with GMATPrep early this year, and I've prevented it from going stale by purchasing additional questions.

Attempt, Score

1. 720 (this is my first look at GMAT mock exams)
2. 680
3. 650
4. 610
5. 520

In case you think this is upside down, the trend is: I am getting worse with practice!

I don't know what to do. Blame the water supply?

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