I only cry in my dreams.?

I have never once in the past decade or so, I am 18, cried. But for some reason, every time I have a dream, which is usually every night and extremely vivid, I cry. Sometimes for stupid things, like a tree dying, or real things, death of a loved one. Only with the second one, the 'loved one' isn't a real person. I have only seen them in my dreams and they reappear repeated in almost every dream I have. Does anyone know what this could mean?