3rd Roommate?

This all happened while I was about 16 or 17 years old.

I was living in a two bedroom apartment with a couple friends of mine (they were a couple) and had left for work early in the morning. Upon my return, around 6 in the afternoon, I did my usual routine of going to the bathroom, got changed and went to make some food. After dinner, I went to use the bathroom again and as I walked in I noticed it was steamy and hot as if someone had just gotten out of the shower. There was lots of steam on the mirror. I found this really odd because I was the only one home and had been home for at least half an hour at this point. As well as the fact that it wasn't like that when I initially went to the bathroom after I'd come home.

Just to double check I called one of my roommates B. She said she left the house at about 2:30 pm for work and our other roommate P left just after me that morning. The apartment is decently ventilated so I don't see how it could've stayed that steamy for that long anyway. Thinking back now I would always hear strange noises in that bathroom but just wrote it off as an old apartment.

Another time, which didn't creep me out as much but it was still pretty odd, I was home with B (P wasn't living there at the time) and was about to start packing for a little sleep over at my boyfriend's, at the time, house.

Now I can definitely be a little messy but my room is more like an 'organized mess' so I still know where everything is. So anyway, the bag I wanted to take with me I had left on the floor at the foot of my bed but when I went there to grab it, it was gone. I tore my room apart 3 times and ended up cleaning it in the meantime. After looking through every room in the apartment, including B's, I had almost given up. B even helped me search for it. Eventually, after we had both given up and she had lent me one of her bags, I walked into my room to see it, in the same place I had thought I left it in the first place, on the floor at the foot of my bed. B swears she didn't put it there and is adamant that she definitely checked that spot and couldn't find it.

The only other strange thing I can remember about that apartment was every single time I walked into B's room, the lights would start to flicker very quickly, but the second I left the room it would stop. The lights wouldn't flicker for anyone else but me.

I would love to hear everyone's opinion on what they think I experienced.