I don't think that explains everything.
Dr. Ong Hean Tatt has tried to explain such strange 'sightings' and creepy feelings from a feng shui perspective in his book 'HAUNTED BUILDINGS: SCIENCE AND FENG SHUI'. He attributed such events to high 'yin' concentration mostly found around big trees, badly lit areas, etc. He went on to explain that 'yin' areas may be emitting low frequency (possibly infrasounds) thus contributing to hallucinations felt by some visitors.
Some badly terminated electrical cable may emit low frequency electrical fields which causes hallucinations to those who are constantly exposed to it.
Paranormal-reality tv shows like 'Ghost Hunters' will show the investigators actively checks 'haunted' area for signs of electrical fields before moving on to real 'ghost' investigation. In one of the episodes, I watched an investigator interactively engaging a 'ghost' in simple q&a. That is no hallucination, can't be dismissed simply by applying the infrasound theory.
In another episode, armed with a heat sensor they caught a 'a full bodied-spirit' hiding from them. Only their special device captured the man-sized figure but not their cameras or even with their own eyes. You will have to watched it to believe it.
My point is, in some cases, if you developed sudden feelings of being watched it may due to 'infrasound' or feng shui will like to call it 'high yin'. In other cases, it may be you are being 'watched'.
Don't worry. it's usually harmless.

could be just a dream...
anyway, if this ever happens again, do take down notes. try to remember every detail.
to qualify this as an outer body experience, i believe certain criteria must be met.
for instance,
1) are you absolutely sure you are conscious and able to make rational decisions
2) do you have control over your movement like moving to the next room
3) does the place you are at seem normal like how it should be when you are awake

Your experience sounds like a dream. dreaming about dreaming is nothing unusual.
I've had that experience before. Thought nothing more of it than just a dream. I dream i woke up twice from a nightmare. Had no control of what just happened other than waking up repeatedly. so no, this is not outer body experience.

I'll have you know, ghost can be funny too