I'm sorry that you are having a frustrating experience with this test.
Your scores on the official practice test averaged around 700, so the first task is to figure out why those were so much higher than your official tests. There are a number of reasons this might occur.
Let's start with the broadest question. Answer this before you keep reading:
(1) Is there anything (for the above or anything else) that felt different about the real exam compared to your practice exams? What were those differences?
Now let's get more specific:
(2) Did you take your practice tests under 100% official conditions? You stuck to the time limits given, you didn't pause the exam, you didn't give yourself longer breaks than allowed, you didn't eat or drink during the test, you didn't look at notes—basically, you didn't give yourself any kind of artificial advantage that you would never get on the real test?
(3) Had you seen any of those problems before, maybe while using the forums here or elsewhere? If you did recognize any problems on the tests, then it could be the case that your score was artificially inflated. I'm guessing this is probably not the case because it would have had to happen multiple times on each test for 6 tests, but I want to make sure.
(4) What were your Q and V scores on your official test?
Everyone has a "range" of possible performance, not just one score that they will always hit. So one of the tasks is to figure out how to
peak on test day—how to hit the top end of your scoring range. On your practice tests, the lowest Q score was 42 and the lowest V score was 45, which together are about a 640. So it may be that you basically hit the bottom end of your range on test day.
That's not an uncommon experience (fortunately and unfortunately). Everyone's at least a little more nervous on the real thing, and some people are much more nervous, to the point that it actually impacts their scoring level.
(5) Did you feel any of the following symptoms? Heart racing, sweaty palms, dizziness or nausea. Difficulty concentrating—find yourself constantly thinking about anything other than the problem on screen right now (how you did on the last problem, the person in the next cubicle who keeps sniffing, whether you locked the door when you left your home this morning, etc). Having to re-read something—you read it, you realize that you have no idea what you just read, you re-read it—and this keeps happening. Having difficulty making decisions—you keep agonizing back and forth among V answer choices, for example, or you have difficulty deciding which math approach to use on a problem. And when it gets really bad: You just want the test to be over, you don't care anymore, you'll pick anything just to get it over with faster.
Those are all symptoms of performance anxiety. Your brain goes into "fight or flight" mode and you literally cannot process in the way that your brain normally processes things. When this happens, people often say that they were fine—because they had a lot of adrenaline pumping through their system, so they think that they felt that they had a lot of energy, etc. But then when we start talking about the details...they realize that they weren't actually paying attention / mentally processing in the way that they normally would on a practice test.
Also, you mentioned that you took our course. Did you already do your Post Exam Assessment? (The meeting that takes place after your official exam.) If not, send an email to our student services team (
gmat@manhattanprep.com) to request this. If you did already do this, please also email your PEA teacher to ask for further advice, as s/he will know more details about your case than I do. (You can also link this post in your email to the instructor so that s/he can see what we're discussing here.)