What does my dream mean?

So I have had similar dreams to this one on numerous occasions, each dream is completely different but yet the atmosphere is the same. I find it hard to describe what happens in the dream because I'm basically dreaming about thought there are no objects, people or really any setting in these dream. I remember the dream is really really dark and there is a strong sense of death as in spending eternity in nothingness. When I wake up from these dreams I usually have to get up and walk around the house for a while, I don't know what the feeling is when I wake up but its horribly depressing. When I was way younger and I had one of these dreams I started screaming when I woke up, my mam came into the room and asked me what was wrong and I randomly said "the leaves are falling". The next morning I didn't even remember the event until my mam reminded me and then I had a vague recollection of her coming into the room. I'm not a sad type of guy, I think about death sometimes but I love life and I'm usually happy and having fun. What do these dreams mean?