Can you play some relaxing music in your room? Something to help you feel peaceful? They sound like awful nightmares, I certainly remember the emotional nightmares about death. I know for me a homeopathic sleep spray helped (Brauer's Insomnia Relief).
I know you remember the pain, but as Jellymaker points out, you know how to do this, your body has done it three times and you know you can do it. Perhaps having a plan to work through pain (maybe some breathing techniques or a plan to get to some warm water) will help you feel like there will be something you can 'do', and reminding yourself of things like the fact that labour won't last forever, it will start, be an effort, but it will finish and at the end you will have your baby. xo

All the best as you work through this. Sorry if I haven't been helpful. xo