First off, have you looked into and thought out whether this feeling is in your head? Have you seen shadows out of the corner of your eyes, smelt anything out of place, heard any oddities that were unexplained? I ask this because often times spirits or entities not attached to the physical plane can often work through the olfactory senses.
Now if you have confirmed this I suggest asking said entity what it wants and meditating and opening up your mind for response. Now it more than likely won't be words you hear in your head it'll be a feeling or something along those lines. If whatever happens in the following moments feels good then, leave it be it is a nice entity :D.
If not, then I suggest asking it to leave, if it doesn't then do a cleansing and if that doesn't work. Do a banishing. That should do it.