Sad dreams

So, last night I had this dream I was hiking with a group of people. Terrain suggest it was somewhere out west. I didn't know the people I was with, but the feelings were they were kind and friendly. At some point in the trail, we encounter a large cat ( think lion, not Garfield). Everyone starts running away, and the cat takes off after them. I try and attack it, but it catches all of them, kills everyone but me. The next scene was me in a hospital room, almost like a decontamination room. Two doctors are scrubbing my whole body. Almost as a burn patient has the old skin removed. For whatever reason, they can't give me pain killers, and it's extremely painful. The whole time I'm standing there, I'm crying, partially from the overwhelming pain, but also not being able to save the others. When I woke up, I was just overcome with sadness that seem to stay with me all day. Sometimes I really hate remembering dreams..