Hey there @gratefuleveryday! I'm @silvertop's other half and the optician. You are right; in the time between exams and the RX change, your brain is having a bit of trouble realizing reality is good. The old RX is comfortable like a nice worn pair of shoes or jeans! The only trouble with going back to the old, is that it will impact your ability to adapt to the new. I would take your old ones with you for the test, but start the day out in the new. Going forward, try not to go back to the old as it's like taking one step forward and then 2 back, because we crave what we know, and your eyes are no different.
However, if after 3-4 weeks of wearing nothing but the new ones; if you're still having trouble, consider having the doc do a recheck. I've seen doctors write down the wrong numbers before in an RX and I've seen people respond badly during exams because they were have an 'off' day. It happens.
Good luck on your test and take care! !LADY