Past lives?

Have you ever had a dream, with the feeling of nostalgia to it?

I've been having alot of strange dreams lately, where I completely stepped out of my current perspective and was a different person, gender and time included some going back several decades. I had a different voice and frame of thought. There have also been dreams where I had the perspective of an animal. I was running on four legs, there was the moonlight, the crisp smells of the rocks and earth, and the river near by, with the feeling of the "present" more steadfast and real than its ever felt in reality; I came to the stream and peered into the water but before I saw the reflection I awoke.

Every time I wake from a dream like this, I feel mournful of a life I've lost.. I feel Nostalgic..
Does this mean anything?
Anyone had any similar experiences?