Dissapointed! 640 (Q44, V35)

Hey All,
So i completed the much awaited GMAT exam today and well to my frustration scored 640 (Q44,V35). Had to go for some therapy shopping to make myself feel better(women and shopping ) Unfortunately this score is lower than what I need to go to the school/program of my choice.Perhaps I had understimated the GMAT and overestimated my abilities.
However, I would like to say a BIG THANK YOU FOR ALL YOUR SUPPORT AND HELP IN ANSWERING MY INNUMERABLE QUERIES!!

Well the minimum initial score on the MGMAT Tests and GMAT PREP tests were all above 650. I was surprised to see this score considering my expectations were much higher. There are no excuses for my performance as I gave it my best shot given my circumstances(full time job being one of them and crazy night shifts, I work in the biotech field so we have processes that run 24 hrs!).

I believe that nerves may have been a factor as I spent a crazy amount of time trying to solve a question that I knew I was capable of solving but I drew a complete blank. Then I proceeded to guess on a couple of questions that I knew I did not have sufficient time to solve these might have been 5-6 questions.
My verbal scores on my practice tests may have been inflated given the number of repeats. Honestly, I did not spend as much time with the verbal section as I was focusing more on the quant. For my next test 1000SC,CR,RC here I come!!!

From my experience the questions are slightly tougher than the GMAT prep practice though not impossible to solve.I did have gaps in my Quant as I would regularly get stumped on DS questions especially those related to number properties.

However, for all you test takers, a word of advice is to do a SWOT Analysis, find your strengths and weaknesses. But, do not just focus on your weaknesses, you need to maintain your strengths and this involves a lot of work. Another point as many before me have mentioned, confidence is key you need to know you can solve these questions, dont guess(like I did) build on your speed and accuracy.
My main worry from hereon is when do I do my next test. Should I take a break of say one week and then prepare for 4 weeks. My problem is that I am leaving for London on July 1st, I will be there for a month, doing a course there in finance.

Is 4 weeks sufficient ? I would like a pessimistic opinion. I would then consider taking the GMAT on my return, that would be in October. Would that be too long a gap? Its safe to say that I really am in a fix! Also do you think I should attend coaching classes?

Your thoughts would definitely help. Thank you for your support.
I may not be as smart, but hell I do intend to persevere!!!