Dream: Battle

Every once in a while I have a dream that consists completely of a battle. These dreams are usually extremely long, very very detailed and gory. They take place in different time periods. I am always a male in these dreams. I wake up exhausted with feelings of post traumatic shock. It wears off, but still -these are some of my least favorite dreams.

Last night I seemed to be an ancient Celt. I think my name was Drusten? That's what my countrymen yelled at me when they saw me on the battlefield, warning me or calling for help.
We were not speaking English in this dream. (Although, it's my subconscious, so it must have been English, but I woke up remembering words that were shouted, and they were not English. Although I do remembered what they meant.)
We were fighting an enemy that in my dream seemed extremely alien to me, but now that I'm awake I realize they were Romans. We were losing. These Romans seemed like demons to me.
I carried a giant double bladed axe. I was one of the only men in my tribe who could weild it, which was a great source of pride to me. It was a formidable weapon, and did cut through the Roman armor, if I was lucky enough to land a blow. I killed so many people in this dream. But the Romans were faster, more numerous and better armed. I was shocked by how many of countrymen fell around me. I saw my father fall. I was too late to save him, but I cleaved his killer nearly in two with my axe. My father had been an important person in my tribe, which meant that I must now take his place. I tried not to think about it during the battle.
I can't remember the end of the dream. Just the image of looking around at all the carnage around me and realizing that these foreign demons were going to be victorious over my people. My people, who have never lost a battle.

These battle dreams are very disturbing. I live every moment of the battle, and I can remember details you shouldn't remember from dreams: pain, smell, the feeling of rain and blood in my eyes as I try to see, increasing fatigue, sunburn and dehydration. These are senses I shouldn't be experiencing from a dream.