Hi dinny,
I wonder if you've been traumatised by your midwive's display of panic and fear. Women are intensely vulnerable during labour, but particularly during second stage and around the moment of birth. Displays of intense anxiety by caregivers and partners almost burn themselves into your brain if they happen at certain very sensitive moments in the labour, and can cause lasting distress.
I had quite a bad SD at my homebirth. My son was 10lbs 12oz and got stuck for a good 6 minutes. I was also kneeling when his head was born and was put into McRoberts.
The difference for me was that my independent midwives didn't display ANY panic and there was no shouting or pfaffing around. Both midwives had a go at extracting him - the second one succeeded and they calmly resucitated him on the bed in front of me. I was fine after the birth, as was my son. I look back on that day as one of the most wonderful days in my life.
I was a bit nervous next time around but went ahead and booked another homebirth (same independent midwives), but ended up delivering in hospital as labour was very long. The actual birth was completely straightforward.
I think my midwives reacted with sensitivity because they were very well prepared. They knew my baby was a biggun and that SD was more of a likelyhood. They'd revised their SD 'drill' and so were able to smoothly go into the procedures without any delay or hysteria.
You'll see a consultant during this pregnancy and he or she will go through the options with you - picking carefully through the notes of your last labour. If you decide to opt for a vaginal birth you're likely to have two experienced midwives in with you who are well prepared to act quickly and quietly in the event that the SD occurs. It is worth you remembering that the vast majority of SD's are resolved with McRoberts without significant damage to mum and baby.
I would second you talking to someone knowledgeable about your first birth - really having a good debrief. You can also debrief as much as you like on mumsnet - there are always many of us here who want to listen. I was also wondering whether it'd be worth your while seeking hypnotherapy for your anxiety if you decide to go for a vaginal birth. Th supervisor of midwives at our local hospital gave me the name of a therapist from the London College of Clinical Hypnosis who specialises in childbirth issues. I'd be happy to pass it on to you if you are interested.