Similar here. Had a miserable time with my first labour, but thought that I had coped with the distress - after all, I had a healthy baby at the end of it. Ha ha ha. During my labour ward tour towards the end of my second pg the midwife noticed that I was getting quite upset (in fact very angry, but trying to keep it under wraps) and asked if I wanted to have a private meeting with her in her role as the midwife who specialised in talking with mums after labour.
took her up on the offer and spent about two hours with her going over my notes in great detail. She listened to me in a completely open and non-judgemental way. Explained what had happened and why, and was frank when she could not explain why certain things had happened. She accepted my anger and distress, and feelings of humiliation as perfectly valid. Above all, she effectively gave me permission to say "No" when I needed to do so. Which I did, when I came to the hospital in labour a few weeks later. It made such a huge difference to that labour, which was vastly better than the first one.
Unlike you, I didn't realise that I had unresolved issues over the first labour, until it was nearly too late to deal with them. But when I did deal with them, and had had this 'debriefing' with the specialist midwife, I felt so amazingly better. I was able to look forward to the labour with confidence in my ability to birth the baby, rather than in fear of repeating the previous miserablness.
And, you know what? Having a good birthing experience wiped out the memory of the bad one. It's a bit like the memory of labour itself - you remember that it hurt, but you don't actually feel the pain any more. I remember that I was very upset by the labour, and some of the events that upset my, but I no longer feel the distress at all.
Having had a decent birthing experience, and through that having learned to trust my body's ability to birth a baby, I then went on to have an amazing third birth.
Go on, take that first step - talk to the hospital...