Feeling SUDDEN loss of "charm" or accuracy on Verbal Questions

During my prep, I scored well in mocks, bagging 700+ on any random day I took them. I believed my Verbal had improved from V33 from last attempt in the official exam to V40 ~ V42 (in official mocks and gmatclub tests mocks). Just before 4 days from another attempt, I felt a SUDDEN mental block in my head. Something was bothering me, I don't know what. In those last 4 days before the judgement day, I found myself lost in verbal practice tests. I could not get ANY of the practice SC, CR, RC question right before the exam. I feared my fate was sealed and now I have to somehow figure out how to overcome this strange feeling.

Finally the day arrived, I was surprised to find myself so calm during the exam. I started with verbal section, feeling astonishingly pleased how calm I was and how smooth my responses were! (at least that's what I thought). I was quite happy with my take on verbal section. I took the optional break with a slight grin on my face. I had some refreshments, drank some water, went to the washroom and all those small gestures you do while on a 8 minute break. Now, it was time for the Quant section. I am not good at it but I believe I am better at quant than on verbal, as most of us engineers are...

To my surprise (I know... too many surprises lately... right?) I found myself struggling on Quants. Questions seemed quite tough and convoluted. But sometimes there were streaks of easier questions. This is not good though, I thought computer must be feeling pity on me, that's why it started giving me easy ones to solve. Somehow I finished the Quant section took the 8 minutes of rush break. There was no grin on my face this time around.
Ok, time to finish it off with IR and AWA. Those sections went fine, although, I did not prepare much for the IR and AWA. 3 hours flew by, I believed I gave everything I had in me on that day to write this test. I was anxious, exhausted and afraid when the computer screen was in transition to show up my scores.

I know you might be thinking this anecdote will have a pleasant plot twist and I would have been victorious on that day; BUT NO!!; No magic fell form the stars. I finished the exam, screen flashed the score of 570; Q48, V20, IR 5. I canceled the score, picked up my stuff, slowly walked away from the test center and hailed an Uber. There was no grin on my face that day.

The reason I am writing this experience, sitting in the cafeteria of my office on a random Wednesday, about the exam which I gave some 17 days ago is not to de-motivate anyone. I am still a believer of the saying - " Just because things don’t always happen when you want them to doesn't mean they never will"

I was just wondering if anyone else have had this kind of an experience and how did they manage to come out of it. Round 1 applications are at the door. My previous non-cancelled GMAT official score is 640. It would be helpful to know any strategy/method to improve scores (if its not too late), Although, I am open to the idea of applying to B. schools with the last reported official score at hand. However, more opportunities would open up if I happen to improve my scores.