I will not endure people being in my bedroom who I haven't specifically invited in. I am inflexible and obsessive on this point, and I make no apology for that.
There are a few problems with this attitude. First, there's a big closet in my room, and most of the clothes in it aren't mine. It's just seen by my family as a convenient storage space. Second, I like to be messy and my mother is a compulsive cleaner.
When I came back from America, my room was not as I'd left it. It was barely recognizable, actually. The floor with its unwanted clothes and dirty tissues had been cleaned up. The bottom bed with all its messy clothes and assorted odds and ends had been cleaned up. My bed had different sheets. (I'd had those sheets for around a year without ever cleaning them.) The top of the (unused) dresser with all its random junk had been cleaned up. The ceiling fan which I never ever turn off was off, and the string to turn it back on had ripped. When I first saw the damage, I was hurt but thought I'd be okay.
I was wrong. That night I got into bed and found that I couldn't sleep. Nothing felt right about the room, and the longer I lay down in that room the more disturbed it made me. It wasn't just the floor and the bottom bed and the shelves and the top of the dresser were different, though that was certainly enough to drive me crazy. The top bed I sleep on didn't feel like I remembered. Even the pillow had been changed, and that pillow has been there for years. I couldn't sleep in my own room on someone else's pillow!
I looked desperately around the room for the pillow but it wasn't there. I ran upstairs to see if I could find it around the laundry but it wasn't there either. At this point (and please keep in my mind that my emotional state was further exacerbated by tiredness and jet lag), I wanted nothing so much as to scream at my mother, "WHAT THE HELL HAVE YOU DONE WITH MY PILLOW?". So I took a piece of paper and wrote a very rude note about how there must be something wrong with her if she couldn't let me come home to my own room the way I left it (when she knew I wouldn't approve of what she'd done), and I put the note on her keyboard so she'd see it in the morning.
But that wasn't enough. When I went back to my room, I still couldn't sleep. The bed was all wrong and the floor was all wrong and the lower bed had everything in neat little piles where I'd never find anything because in the old mess I knew where everything was and now all the random clothes I'd never wear were together. It was all wrong! That was barely my room anymore! I picked up all the clothes on the bed, and started throwing them around the room. So it wasn't like it was before, but at least it was messy again. At least I could pretend that this was still my room.
(This kind of event is known as a "meltdown".)
The next morning I'd calmed down, and went to apologize to my mother. But she apologized first, and gave me my old worn-down pillow back. So while my room was still very wrong right now, it would be better.
Later that day my father got brought into the argument. Unfortunately for me my father is every bit as stubborn as I am. He repeated over and over that there are rules in this house which need to be followed, like not having dirty tissues on the floor and dusting and vacuuming regularly, which are done for the sake of health, and since I won't do these things myself they "need" to come in and do it for me. And I repeated over and over that they were to stay out of my room, and that this was non-negotiable. We didn't get anywhere.
Things settled down. I put most of the clothes from my floor back onto the lower bed. I slept well.
A week later, I came back from Games Night and found that my floor was distinctly cleaner than it had been. The backpack I'd taken with me on the plane was gone, and a pair of pants that I'd left on the floor was on the lower bed. Again I couldn't sleep, so infuriated that someone would go into my room while I was out and mess with my mess. I considered banging on my parents' door, waking them up so that I could start yelling at them, but I realized that would also wake Dena up, and I didn't want that.
I lay in bed unable to sleep, trying to figure out how I could prevent this from being a regular occurrence. Could I lock the door? No, it's just a skeleton key, and my parents have a skeleton key. Could I switch the locks to something more secure? No, I don't know the first thing about locks. That would get complicated, I think. Plus, they'd most likely steal the key and copy it, and then what would I do? Could I block the door?
I could block the door. I got out of bed and moved what was left on the dresser to the floor. Then I started pushing the dresser toward the door and didn't stop until the entrance to the room was blocked.
The bed is next to the door along the wall. The dresser is along the other wall, and next to it is the garbage where I throw all my dirty (and sometimes bloody) tissues (and usually miss). In between the two is the way in, and that's where my dresser is now. There are only two ways in now, short of moving furniture: climb onto the (elevated) bed and drop down, or climb over the dresser. I figure my parents would be much less comfortable climbing around than I am, not least because of their age. And if (over time) I get slightly stronger limbs out of the bargain, no problem.
Once I'd set this up, I was able to sleep again.
That day my father and I got into an argument, because he'd been the one in my room. He wanted a shirt that was in my closet, and while he was there he noticed things that belonged to him and took them. I tried to tell him that this was unacceptable, that if he wanted something from my room he'd have to ask me for them, and that if I was out of the house he was out of luck. And he tried to tell me that the room needs to be clean, that I need to keep my clothes folded and in piles, etc. etc. And I said the argument wasn't about his silly rules, it was about them not going into my room. We could discuss me taking out dirty tissues occasionally, or even vacuuming every now and then, but first they needed to promise me that they would stay the hell out of my room. My father agreed.
There haven't been any more fights since then. I've kept the dresser in place, because I don't trust my parents. So the layout of the room is different, but it's my room again. So I'm content.