you should retake, you may score a pretty big increase on the second attempt.
When i first took the gmat i scored a 460, one month later a 570. I would recommended you pay close attention to your "splits" when i took the gmat here is what i did...
Firstly, i took the first five pages of the gmat scratch sheet and wrote the following quant splits:
75 - 0
60 - 7
45 - 14
30 - 21
15 - 28
and one page of the gmat scratch sheet and wrote the following verbal splits
75 - 0
60 - 8
45 - 16
30 - 24
15 - 32
RC: I. II, III, IV
What this let me know is when glancing at the clock, where i needed to be at on the test. For example, after i past the 45 minute mark on verbal i would cross out the 0 and the 8 so i can keep track of approximately how many problems i had left. Also, after each reading comprehension passage i would cross out one of the roman numerals so i know how many passages i had left. After sticking to this method, i felt as if i had a lot more time during the exam to concentrate.
Ultimately, after four attempts i wound up at a 590..many people will say this score is horrible but i feel its an accomplishment as i experienced a significant increase from my first attempt within a six month time period.
HTH