Hi
Bhu750We are so sorry that you had such an experience!
Also, we are glad that you have been provided another test opportunity.
Pls connect with GMAC at the earliest in case you think of taking an offline attempt.
We suggest you to take up an attempt where you "feel" confident and can perform your optimum without external distractions.
If you are trying for the after 3 weeks here are our few pointers on it:
(1)Always keep yourself in a test simulated atmosphere experience. Take mini tests/quizzes/full length og test(we suggest retain 2 at least for a next attempt if needed.)
(2)Since your goal is 770 and your recent mocks are 740,we suggest to touch on Advance questions from the subject area. Use verified resources like OG/QR/VR/Retired old questions.
(3)Create a schedule that contains a break day every week, Break away from Gmat prep for one day completely ! Our system needs time to shut down too so that it can start afresh. We advise all our students to keep a day of break knowing the side effects of a burn out

.
(4)Commit to the schedule you have created. Make it practical with some buffer days as reserve.
Most importantly, don't let this experience hover on your mind for long.
Your mock score reflects your hard work and soon your real score would also reflect the same!
All the very best. You can get in touch with us for any disclarity.
Thanks
D.S
GMAT SME