Hi there, I am hoping i'm not too late posting this! I was in a similar position... After a failed attempt at the HyCoSy whilst I was awake, I had this proceedure done under GA (around 8 months ago now). For me personally, this wasn't an issue as I've gotten more used to GA :-) but I understand the fear. The proceedure was less than 15 minutes and I felt compeltely normal when I was woken up. I was told that the entrance was just a little "fiddly" - which isn't unusual for us trachelectomy ladies!
Since then I've been undergoing more fertility investigations under a different specialist and they have actually been able to insert a catheta whilst I was awake. As with Amyrose, this was whilst I had my period (nice), it was a good 45 minutes of prodding with a very thin catheta! Once they'd found the entrance, then they were able to do this 3-4 times without trouble.
I know it's easy for me to say, but you're not alone, I completely understand as I feel like this too. There's a VERY good chance they'll be able to access your womb, and if you are having periods then there's definitely a way in. It's just that our anatomy is different and the consultants need to "draw a map"! I've had 4 people try now and only 1 has succeeded whilst I was concious.
If you want any advice or have any questions about the proceedure please do pm me and I'll try to help!