A nice surprise--but worried about Quant score

I originally scheduled my GMAT for August but panicked and rescheduled it for last Saturday instead. My study plan was a 'whenever I can' plan (unfortunately that's what my sched permits)-- I used the Manhattan GMAT books, the OG Quant and OG 12th edition. I found that combined with GMAT Club tests/forums, that's basically all you need. The OG had tons of questions that looked familiar on test day. I was not nervous at all going in, because I figured I had already spent $300 on this test, did what I could to study, and whatever happens happens.

One thing I didn't practice enough in my CATs was timing--suffice it to say, I nearly ran out of time in the quant section. The stress kind of got to me. I for sure guessed on a few questions. I downed a red bull right after the quant section.

In my verbal I got FOUR reading comp passages! It was crazy. I figured if I saw that many, that I must have been doing pretty well.

I submitted my scores and saw the result: 630 (36Q/40V). Not sure of AWA yet but confident thanks to chineseburned's guide. I'm personally happy with this, as I was getting 590s in my CATs.

...But I'm kind of freaking about the weak quant score. I have good undergrad quant grades (4.0 in finance, 3.0 accounting), and I'm hoping that if I use this in my essays that it will translate. My schools are Vanderbilt (av GMAT 660), UC Irvine (av gmat 670) and safety U of San Francisco (av GMAT 590), all Round 1. I am hoping for the best!!! No plans to retake at this time.

Thanks for all your help- I'm a lurker on the boards but there has been a lot of information I've gotten from this site.

--Kristen