Nightmare about a ghost, what do you think it might mean?

we moved into a new house a few months back, and I really like it, like my room the area, everything really. last week I had a nightmare that is really freaking me out now. It was night, and I was walking around with I believe my mom, and a lady I've never seen before. as we walked by my room and looked in I saw a head of a lady turn very sharply and look straight at us, her mouth open as if she was wailing, she looked crazy, we all screamed and ran into my sisters room and that is when I woke up. what on earth can this mean? the only part of the house I feel uncomfortable in is the basement, but that's pretty normal is it not?