Dear Milli,
I'm happy to respond. My friend, I am genuinely sorry to hear of your struggles so far.
First of all, I want you to read this post very carefully, because it describes a scenario that you have enacted twice in your life so far.
https://magoosh.com/gmat/2014/lower-on-t ... ice-tests/Read that post, and read carefully the six posts to which it links.
The fact that you can get 600+ on the practice tests is no joke. You are
not a complete beginner if you can accomplish that! Yes, you have some more to learn, but that already shows a decent level of understanding. It seems to me that the BIG problem for you is how stress nails you. My guess is that you have been practicing math and verbal assiduously, but that you haven't been practicing stress management skills at all. I would say that you need to put into practice, in your daily life, all the practices I recommend in the blogs linked at the bottom of the above blog, especially #4 "Many Practice Recommendations for Stress Reduction." You need to practice all that as serious as you practice math and verbal, because it looks as if, right now, stress is making a far bigger impact on your score than any academic knowledge could.
I would also recommend implementing habits of excellence, especially if you have dreams of getting a 700:
https://magoosh.com/gmat/2014/gmat-study ... 0-or-more/Getting a 700 is not just a matter of learning all the cognitive material, all the math & verbal. It's all about the kind of person you, the kind of attitude and energy and confidence and stamina that you carry with you as walk into the test room. You cannot get excellence out of a book. Excellence is a set of habits that informs the way you walk through the world, the way you live every moment of your life. Do you bring the best of yourself to each and every situation as a matter of principle? That is excellence. Excellence comes from the heart. That is the ideal for which you have to strive.
If you can integrate excellence into every aspect of your life, and if, in particular, you can bring the best of yourself each time to the the stress-reduction exercises, then it will be a very different you that walks into the test room the next time. My friend, that is precisely what I wish for you.
I would also recommend checking out that free blog for many good GMAT tips and many free practice problems.
Does all this make sense?
Mike