The best way you can divine the meaning of a dream is to look at the dominant feeling that infused the dream. That is normally what your subconcious is trying to tell you. If you had a feeling of dread that you can trace to being in a room with your mother, I'd guess you feel uneasy about letting your guard down around her for some reason.
Doesn't necessarily mean anything sinister, it could just mean that you're growing older and now keep a few secrets from her that you didn't used to.
But ultimately only you can work out the meaning. The exact content of the dream is relatively unimportant.
-------
Do you have a sister? Then click on my Homepage icon for a warning.