Hey Adithya,
Looks like a typical case of nerves. Above 750s in GMAT prep should easily pull you to above 700 in GMAT, UNLESS your nerves got the better of you.
Many friends llike you in the forum had the same issue. They just took a month's break, revised lightly and attempted again to score closer to their GMAT prep scores.
One thing i guess that happened in your case was, Verbal sometimes throws people's balance and timing off in the beginning. Esp, if you have atleast couple of tough and long RCs in the first 15-18 qs, the more guesses you make the more confidence you lose. Your well toned timing skills go out of the window, due to pressure. So, now you are in uncharted GMAT territory, where your timing is off and you are under a lot of pressure. This combination has thrown a lot of people off from their expected scores. (It's like cricket, with all the game strategies, and run-rate you plan to maintain. Suddenly in the actual match, 5 top wickets are down, and all your strategy goes out of the window. Only the coolest mind succeeds then. )
Just sit back, relax and try to analyze your performance, and remember th questions threw you off. Form a new strategy, brush up your skills and this time expect that the GMAT verbal will try to throw you off, with the worst possible questions in the beginning.
Just give it again, and I believe you will score closer to 750 this time.