From 620 to 710 - I need your help!

Hello Everyone,

today I took my first GMAT exam and scored 620 (Q 44, V 31) and IR 8. My goal is to score 710 (Q 50, V 37).
My preparation so far looked like this:

- GMAT OG (I went through all questions)
- Took my 1st GMAT Prep exam: 640 (Q 47, V 31)
- Started with Magoosh: Went through the Quant tutorials
- Took my 2nd GMAT Prep exam: 690 (Q 47, V 37) - felt quite confident
- Studied the Magoosh questions (around 150 Quant and Verbal)
- One week after my 2nd GMAT Prep exam I took my 3rd: 570 (Q 42, V 27) - the panic started
- Studied another 150 questions each and repeated the incorrect old ones
- Took my 4th and last GMAT Prep exam (this time from Magoosh): 580 (Q 38, V 32)

Now I do not know how I should continue... Do you have any suggestions? (Books, courses, Prep exams etc.)

I am feeling that I have problems with the pressure of taking the exam... Today when I started with quant I was not able to answer the first questions so I started with a bad feeling which got even worse when I felt that the questions became quite easy...

Thank you very much in advance!!!

Best,
Robin