Hi Goosey,
I have a similar problem though maybe a bit less of an issue than you. My heart and bp have a tendency to plummet causing me to pass out. It doesn't happen all that often unless I'm ill, and exercise doesn't seem to affect it though being too hot in our sauna of an office at work doesn't help.
I had no issues in this or my last pregnancy, in fact got high bp towards the end of each one.
What did happen though, was a bad reaction to my spinal for my elcs last time. Ds was breech hence the cs. The reaction Was expected though, (light headed, hot, vomiting) so I was given something to counter it straight away.
Wrt to c section. I had a really great experience! Walked into theatre, wheeled out with ds 40 minutes later. That included time for introductions, catheter, canula, spinal, vomiting etc. The longest part was stitching up I think.i was really anxious about the spinal but it was fine, worked very well in that I wasn't able to get up as soon as some.
The mw were a great help overnight passing ds to met feed etc.
Elcs at 12.35 lunchtime, was up and in shower the next morning. It was painful, don't get me wrong, but not as bad as I thought and there was significant improvement daily. The worst part was sitting up out of the armchair or getting in and out of bed. Back driving after four weeks with Gp approval.
I've had a hard time deciding what to do this time, and am going to try for natural purely because ds is only 18 months and recovery from.natural might be easier Wrt lifting him etc.
Goid luck!