Hi patonhari,
Test Day is a rather specific 'event' - the details are specific and they matter, so you have to train as best as you can for all of them. The more realistic you can make your CATs, the more likely the score results are to be accurate. The more you deviate, the more "inflated" your practice scores can become - and that's what happened here. By taking the CATs at home, taking them at different times of day, anything else that didn't 'match up' with what you experienced on Test Day, etc., you weren't properly training for the FULL GMAT 'experience.' In addition, by taking the CATs at home, you didn't account for that 35 minutes of travel time - time when you'd be spending energy, thinking about the Test, etc. Thankfully, all of these issues are relatively easy to account for - you just have to be more rigorous about making your future CATs mimic the aspects of what you'll face when you retake the Official GMAT.
Points can be won and lost rather easily on Test Day, so beyond the 'physical' factors that I discussed above, it would help to have data about your exact Test Day performance. Have you considered purchasing the Enhanced Score Report? While the ESR doesn't provide that much information, there are usually a few data points that can help to define exactly what you need to work on to score at a higher level. If you purchase the ESR for this recent attempt, then I'll be happy to analyze it for you.
1) What is your goal score?
2) When are you expecting to restart your studies?
3) When are you planning to apply to Business School?
4) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich