As was said above, I agree that you do not want to be put under (unless as an absolute last resort) and also wonder why the need for a cesarean has come up so early!
I've had two. The first one wasn't an emergency, but it was only planned roughly 12 hrs before it happened. I was 10 days overdue and had gone to the hospital for an induction when they did an u/s and discovered he was frank breech. After consult with the dr, we decided it was best to just do a cesarean as frank breech can be a complicated delivery.
The second one, I was a week over and it had been scheduled for a few weeks. I wanted a VBAC, but never went into labor. The office has a really stupid policy that you're only allowed to go a week over (and I couldn't switch because they are the ONLY practice in an hours drive that even allows VBAC attempts anymore and one of only 2 practices in the area that took my insurance). They also do not induce labor for a VBAC.
The second was worse emotionally than the first, because I had that extra time leading up to it to think about it and obsess over it. The recovery was also worse, I think because I had myself all worked up.
During both of them, my number 1 and 2 concerns while in the operating room was the temperature (it was practically arctic in there) and the little oxygen tube they put under your nose. I also felt like I was going to fall off the table, though they assured me otherwise. The entire process took right at an hour each time, and while the above posts are right, you do not feel any pain whatsoever and I did not feel any sort of 'empty' feeling like they're taking your guts out, there is this really odd pulling sensation. Pulling and tugging, like after you've had dental work and you're all numb but you can feel your cheeks move when you talk. It's hard to describe. No pain whatsoever, just... odd.
You do not want to be knocked out because you will that first moment of your baby's arrival. The first little cries. You'll miss being the first person to know their weight, their gender, so see their sweet face. You won't be able to hold them or feed them for hours while the heavy drugs wear off and you'll be groggy for nearly their entire first day on Earth.
One particular thing that helped me get through it calmly was that the anesthesiologist sits on a stool by your head and talks to you. He or she does this alllll the time, so he can see the signs on anxiety (higher heart rate, etc) coming on and will ask you questions or talk about things to distract you.
It is nerve wracking, yes, but if you try your best to not dwell on it for months and try to practice some calming sort of meditation techniques, you should be able to get yourself through it. I'm pregnant with my third right now and unless I find a midwife willing to deliver at home, a vaginal birth is forever out of the cards for this or any future pregnancies, so I'm most likely looking a third cesarean. I think I'll be more calm about this one, up until maybe the day of when my own anxiety will hit, but I know myself and I know that I have an excellent ability to 'zone out' and ignore things that are going on around me if they seem too stressful or irritating to deal with, so that will be my go-to response. I will focus instead on the coldness of the room and think about something else until the baby is out. Maybe you have your own personal coping technique you could learn to use more effectively over the course of the pregnancy.