Zachary,
If you can only take a morning test, I would recommend running on a morning schedule at least a week before the test. If an 8 AM test means you need to get up at 6 AM, then get up at 6 AM for a week. I would also recommend spending at least an hour each morning studying, so that your body is used to doing GMAT problems so early in the morning.
Another thing that helped me alleviate stress on test day was to have my husband drive me to the testing center. The center was in a nearby city with which I was not familiar, and if I got lost, that may have brought back the text anxiety I worked so hard to suppress.
Lastly, do take the time to eat a good breakfast! The test is long, and your brain needs thinking food. You can snack during breaks, but I found it a little hard to have an appetite during the test, despite being hungry.
Best wishes,
Tatiana
Tatiana Becker | GMAT Instructor | Veritas Prep