Don't rule out the possible presence of electromagnetic energy waves in the air. Is there a curcuit breaker or some main wiring running thru the walls near the living room area where you get this feeling? If it is an older house, there is a chance that wires in the wall could be throwing out this energy and giving you these feelings on uneasiness.
I would make sure that there isn't a practical physical explaination for what you are experiencing, before allowing yourself to become more fearful than you already are. And if it is spirit, you really don't want to be fearful anyway..lest it be something negative that is there to feed off of that fear.
Blessings,
Rebecca