This happened a few days ago at my workplace. I was working this opening shift with the same co-worker I always do. I got there first and went into the break room to put my stuff down. As I was putting my bag down on the table, I started to get this distinct feeling that I wasn't alone. Not necessarily being watched, just that I wasn't alone. Then, I started hearing two voices outside the room, a man and a woman. There's a really loud fan in this particular room just off the break room, so I couldn't really hear what they were saying. It sounded like indistinct whispering. I assumed it was just maintenance personnel, but I went to look anyway. There was no one there.
I went back into the break room to finish getting settled, still feeling like I wasn't alone. Then, I heard some loud banging noises like an animal in the vent above me. I was so startled I ran out of the break room. The noises stopped, and I went back inside. This is a noise that my co-worker and I have heard several times and reported several times, but they haven't been able to find an animal or another reason for it. I finished up in the break room and started getting set up for work. As I was preparing some things, I felt like I was being watched and like there was an actual presence in the room with me.
My co-worker showed up and we got to work, and there were two patrons in the room with us, but I still couldn't shake the feeling of there being a fifth presence. Then, one of the patrons just stopped doing what she was doing, focused on something all the way on the opposite side of the room, waved, and said "hi." I looked at the spot she was looking at, and there was no one there. My co-worker turned to me and said, "What was that?" and I said "I don't know. I don't see anyone there."
This is not the first time strange things have happened at my workplace, and I'm not really sure what to make of it.