I had a pretty horrifying dream last night

It started with my talking to one of my Aunt's that I haven't seen in a long time. We were both in the kitchen of my parent's old house (we moved from there about seven years ago)

I forget why but for some reason we started to argue, at that point she changed into my grandmother. My sister walked in at that moment and started shouting at me, I swore at her and left the room. I felt so guilty and embarrassed at behaving in that way that I decided that I couldn't stay at home and I just had to leave. As I tried to find my way out I discovered that it really wasn't my parent's house at all; instead it was some kind of red-sandstone mansion (it reminded me of Castle Coch; a victorian gothic revival castle in Cardiff, which is where my grandmother lives).

I left the mansion (which felt like home but wasn't - this confused me in the dream) and walked out to the road outside, which was filled up with cars, I was still angry and hurt so I got into my car intending to drive away. Unfortunately the other cars were parked up so tightly that I couldn't really leave, nonetheless I turned the ignition key and tried to start-up the car. There was a loud clunk and then my vision was filled with an orange light which turned to white.

A very clear thought came to me: "I'm dead" and I was filled with a real sense of sadness and frustration that I hadn't done everything that I wanted to do in life yet and that I was too young to die. (I'm in my mid-20s)

At this point I felt my skin start to crackle as if I was being burnt alive. I woke with painful cramp in both of my legs.

It was a really intense dream and I felt quite confused after waking up (I remember wondering if I had actually died and if I was now in some sort of afterlife), I definitely had a real sense of loss afterwards due to being killed.

So... does anyone out there have any idea what this means? I don't usually get very intense/memorable dreams at all so I would be curious to know if anyone has any thoughts?