Depressedly ask for advice

I am a girl from a developing country. English is not my first language. I did the GMAT exam some days ago and I only scored in the range of 600-670.

I travelled 10 hours by train to take the exam. I rested a night before the exam date. Booklet and marker were a big supprise for me. I am not familiar to use them. I figured out the marker did not work in the IR section. The officer turned off the air condition.

Math section: 1) I spent 4 minutes for the first question ( quadractic equation- simple one) to double check.
2) More than 2 minutes for the question: What is the x intercept of line k if slope = 4* y intercept?
3) I did wrong at last question : \sqrt{2} = how many percentage of \sqrt{8}?, the question I saw at home few days ago

What did I prepare for Math? - Theory from Magoosh Video
- I did all level 500-600 of gmatclub, and 700 ( but too long ago), scored 48-50 on gmatclub. But I know the pattern happened in the real exam, then I only studied official questions: I did all official questions ( official guide, review, test codes, gmat question bank pack 1, gmatprepfile-800 questions, and real questions happened somewhere on the internet). I expected to score 50 but I scored 49. I always scored 50 on gmatprep pack 1,2 and free.
Verbal section:
- Music and traffic when I started doing verbal. I read first RC passage 2 times. I saw my enhanced score report. I did many wrong at first 20; from 20-30, I did 10% wrong. Questions are not difficult.

What did I prepare for Verbal: Theory from Manhantan SC book, Bible, Egmat account.
- I did all Official questions ( official guide, review (version 10-16); test codes, gmatprep question bank) gmatprepfile~ lastest /comprehensive file; all manhantan SC n CR questions from manhantan CAT (questions hacked); EGMAT Schoranium;

- LSAT for CR: I did LSAT mastery ( questions by topics) and too many LSAT pretest. I did quite well with good time.
- I did 1000 SC and 1000 RC too ( for 1000 RC, I only did GMAT section: more than 100 passages); People donnt do 1000 because it is a ban documents, but that it is a ban documents means it stored real questions)
- 31 test set renew, which I always did 35- 40 correct out of 41

I practised verbal well. I am confident about verbal than about math.

One month before the exam: I practised many maths questions n tried to do new ones. I only reviewed verbal and did documents I did many months ago. Also, I donnt have any new to do because I did almost.


I always scored 750- even 800 on gmatprep pack 1, which I knew some questions in advance, I scored 750 on gmatprep pack 2- exam 5 and 6, which all are new questions.
I got verbal score in the real exam which is the same score I got the first time I did gmatprep mock with 1 week of reading theories 2 years ago.

Please advice me what should I do next? Do I get bad luck? I was to nervous then I could not concentrate or is that truely my ability? I am like a person who just dropped off cliff. All my dreams are gone. All my efforts are gone.
I wana to retake GMAT soon but I have another important professional exam in December, then I plan to retake at the end of December - Jannuary. I depressedly ask for advice!