Shit happens, you are not alone , we all land straight on our face, time to time. There is absolutely nothing to be embarrassed, it was out of your control. Chill out and do not punish yourself for what happened. After all, we all are humans and not robots. The positive thing is you can rewite exam and you will not have to pay for it again (just trying to be optimistic).
The situation was worsened by the fact that the application deadline for your college was near. Maybe even if you had written the exam you could have missed your target score.

Hi Maria,
feeling for u...bt u always get a second chance to achieve what u want..Hopefully u ll score much higher than what had u scored this time..

Cheers,
Suchit

The first time I took GMAT, I almost had a similar feeling. I didn't collapse or anything but my head was spinning like crazy. Same reason: I finished my Quant 6 minutes early and felt that none of the questions were challenging. This thought came coming to me until half way through the verbal. That's when I felt a deep migraine in my brain, I rarely get migraine. I couldn't comprehend the passage and had to skip 3-4 questions and finally I was able regain my composure. I scored 640 in that test.

I retook the test after two months. This time I felt the questions were more challenging and I had to give up few Quant questions because of time restriction. I progressed to Verbal and again, half way through, I started getting worried. I even got a little lazy with the question thinking I already screwed my test. At the end, I got 730.

These would be my recommendations:
1. Take some fruits and nuts (almonds help best) with you. Goto restroom, freshen up and have those nuts and fruits in each break.
2. It's hard not to think about the last section. But try to think positively; even though you might be getting easier questions (I scored 49 on Quant and most of the questions were still easy) you might be doing well. You could have run out of time, but that means you got harder questions. Either way, you might be doing a lot better than how you think you did and try to do better on next questions.

I scored 41 on my Verbal, but had I known then that I was actually doing pretty well on my Quant, I'd have done a lot better.