Confusion

Date: 12/27/2016

This was a dream i had months and months ago, so i was with my current ex but this dream has nothing to do with her really. i'm in this sort of palace looking place, like the stairway in titanic, and everyone's wearing old fashioned clothes, like dresses and waist coats etc. Then, this beautiful girl comes out of no where and she's holding my hand, and i love it. she feels like home. Suddenly, everything has started to flood and we get separated and i'm panicking, trying to find her. i finally find her and it's so good to have her in my arms. Obviously when i wake up, i feel awful because my then-girlfriend was supposed to be that girl but she wasn't. i have no idea who the girl is, i've never seen her before but she felt like home, even in my dream. does anyone know why this is? has anyone else ever experienced this?