I just Beat The GMAT!

Hi all,
I just took my GMAT today and got embarassed by the final score 570 (Q42, V27)... This is even lower (and much lower) than the first score I got after the first GMATPrep simulation I took BEFORE starting studying (that was 630).
I had not much time to focus my studying due to my current job which does not give me a lot of free time (working even on weekends), but I'm a Computer Engineer and I've been working in an English speaking country for more than 2 years, so I felt I didn't need a huge preparation in order for me to break the 700 threshold... In fact, when I got 630 to my first simulation, I felt like I was on the right way and with some studying I could get over 700.
After some studying (OG 11/12 and MGMAT questions), I took several simulations (GMATPrep and MGMAT), and all my scores were between 660 and 720, with partials going between Q40/Q47 and V35/V41.
Important point: I was not confident that I could easily get a score greater than 700 on the real thing, but on the other hand I knew that (maybe with a bit of luck) I could also score even more than 720.

My way to the exam

I took one week off from work to try and finalise my studies, since before this week I was studying on and off only when my job allowed me. On the free weekends, I was taking the simulations in the morning and reviewing them in the afternoon (I never had a FULL weekend off, meaning that I could study either on a Saturday or on a Sunday).
I did lots of studying in this week, maybe too much as I felt I was getting very tired so I kept the last 2 days before the real exam pretty much empty from big study.
The exam was in the morning - maybe this was a mistake as I'm not exactly an early person and I had to wake up at 7am.

The exam

When I arrived to the center, I was extremely nervous. Too much. The ladies at the reception did not help at all, they were not friendly and they made me feel like I was on a concentration camp more than just about to have an exam.
After the normal checking procedure, I finally sat to start my GMAT.
The essays were OK, I was trying to relax while writing them and I think I did pretty good. I will update you guys with the score once I get the results.
Quant part started easily and then got a bit more aggressive, I guessed at some questions because I was not even able to understand what they were asking me (yes! I could not understand the English behind the questions), on most of the questions I was pretty sure of my answers, but I also could see that a lot of PS questions were medium difficulty. I can't say anything about the DS questions because for me they are ALL medium/high difficulty. So, I was expecting for my Quant bit something around Q44/Q45.
I had the break after the Quant, drunk some water and went to the toilet. I thought that the Quant part was not bad after all, so if I had achieved an excellent Verbal part, I could be in the 700 eye. I started to get nervous, because I was thinking if my Verbal was just little worse than "excellent", I would have not touched the 700. I went back to my seat and started the Verbal part. After 5 minutes I wanted to go again to the toilet. After 10 minutes I BADLY wanted to go again to the toilet. After 15 minutes I was looking at the timer thinking "OMG, I still have 1 hour before I can go to toilet!". Lesson learned: never drink too much water during this exam. Basically, I think here is where I lost the game. I was not calm anymore, I started to twist about on the chair, trying not to think that I wanted to go the washroom. I would say NOW that I would have done better if I had gone to the gents, losing 4 minutes (2-3 questions) but coming back ready for the final sprint - obviously this is not what I was thinking in that moment (you are allowed to laugh at me!).
After finishing, the score I had was that freaking 570. It surprised because even though the Q partial is more or less what I was expecting, the V partial was lower than I thought I did - in fact was my lowest partial score ever.

So now the point is: I have to retake it and I want to be confident enough that the next time I will actually score more than 700. This time I was not at that point that I was sure to score >700, even though my final score (570) does not reflect my average performance, I was also hoping in a bit of luck to exceed the 700. I found Manhattan GMAT as an invaluable source, those problems are tough (in my opinion a bit tougher than the real GMAT ones), but explanations are great and the concepts they test are definitely the right ones. So I would like to stuck with MGMAT: I liked it, I'm already used to it and with the time constraints given from my job I don't have time to experience something else that I could regret. I bought the MGMAT Internet set (question banks + simulations), I did pretty much all of them and I tried to understand all the concepts behind. No concept on the GMAT is new for me (I'm an engineer), but the way these concepts are tested is definitely new, and I personally do NOT like multiple choices exams.
I would ask some of the brilliant MGMAT tutors over there or any of you guys to suggest me some kind of source that I could use to improve my score and getting confident that I WILL score >700. I feel that in this test confidence is everything.

Please feel free to share thoughts and give me suggestions: I need them!