Ask to speak to the anaesthetist tomorrow before they prep you for the c.section. They may have something they can give you help you feel calm throughout, sometimes just knowing s/he is there for you, looking to keep you safe and calm can help. I was really scared before my CS, for a couple of reasons, and I found talking to my lovely anaesthetists beforehand was great. I had their assurance that if I started to feel weird at any point all I need do is tell them and they would be right onto it straight away.

Good luck, remember you will come through this, it will be behind you and you will be holding your precious bub in your arms.