Qhoc,
I experienced a similar disappointment when I took the test for the first time 3 months ago. Quant part was rather easy even if I probably did a mistake among the 1st 10 questions and only scored 49. On the verbal side, timing screwed my chances up. SC was not looking like the ones I used to solve, RC was doable but tough and on top of that RC was awful with also a back to bak RC experience. I finished the verbal part with 30 seconds left and scored 31 for a total score of 650, at least 50 points below my objective.
If you go through all the posts of these threads you will notice that we are not just 2 to have this hard time especially on verbal. There are several ways to explain that : bad luck, bad concentration and context (previous night, overall noise, 1st cat test...). I prefer to consider that I was not ready enough cause if I were whatever the questions or the the guy close to me who was reading loudely all the questions, I would have cracked the verbal too.
To conclude, if you want to score 700 just target 750, if you are aiming 750 target 800.
Hopefuly this site is also full of great experciences of guys who did not give up after a 1st failure and finally defeated the beast : they all are inspiring examples !