Friendly Spirit (2)

I've always been interested in the unknown (spirits and such) but haven't had an 'experience' for about 4 years, and have never had any encounters in my own home, until very recently.

The first 'occurrence' was about a month ago. I have a personal alarm that my overprotective mum gave me which I usually just keep on my bedside table. It's small and square (about half the size of a matchbox) and has a string attached to a pin; which you pull out to set off the alarm. This pin isn't easy to pull out; you have to twist it then pull hard. I've had this alarm loose in my handbag and school bag and the pin has never fallen out (despite the fact that I'm not careful with my bag and often throw it down with force). About a month ago I was in my room, the alarm on my bedside table as per usual. I hadn't touched it, nothing had bumped it - but when I left my room and made my way down the hall it went off! I ran back into my room and the pin/string was sitting neatly on the opposite side of the bedside table to the alarm. No one had gone in my room and I hadn't knocked it. Even if I had - the alarm went off when I was well out of my room, so I couldn't explain it.
The second incident happened within a few weeks of the alarm going off. It's been incredibly cold at night lately, and our gas heater hasn't been working properly. On this night it was particularly cold, so my mum and I were taking turns in trying to turn the gas heater on. It refused to work so we gave up and went into the lounge to watch T. V. In an ad break, my mum went out to try the heater again and yelled out. I came out and asked her what it was. She explained that when she came into the family area to try the heater - it was already on and turned up on high! No one was home except mum and myself, and neither of us had done it.
The third incident was the night before last. I often fall asleep with my light on and that night, I had done so again. I remember waking up and seeing my light on, wanting to turn it off but being too tired to reach over and do so. I rolled over and fell asleep. I was still conscious of my light being on but wasn't too bothered about it. I woke up a few hours later in darkness. The first thing I thought was my light - it wasn't on. Like I said, when I woke up previously I had been conscious of it being left on. I knew I hadn't turned it off, I'm a very light sleeper so if I had woken up to turn it off I would have remembered, and I never do things in my sleep, so I couldn't explain it. I asked my mum in the morning if she had come in and turned it off, but she hadn't.
The final incident happened this morning. Normally on my bed I have 5 pillows, two side by side, one on top of each of them (so 2 pillows on each side) and then one in the middle. Like most people have 'habits' with the way they arrange their pillows when they make their bed and sleep, that's mine. Anyway, last night I'd been uncomfortable and thrown one of the pillows on the floor next to my bed. This morning when I got up, as I went to leave my room I turned around and contemplated making my bed. I actually consciously noted the pillow on the floor, I have no idea why, but I did. I'm quite particular and it annoyed me, leaving the pillow on the floor haha. But I decided to have breakfast first, wash my face and then clean up my room. I had breakfast and washed my face, and went back to my room. When I got in there the first thing I noticed was my pillow - it wasn't on the floor anymore. It was placed behind another on my bed, in the order I usually arrange my pillows in. I knew I hadn't done it. I'd consciously noted the pillow on the floor as I left my room, and yet when I returned it was neatly arranged on my bed. No one was home but me.
I know these occurrences probably seem petty and stupid but there really is no other explanation for them! The only thing I can think of is that there is a friendly 'spirit' hanging around :)