Feeling that I'm not really here
I'm wondering if anyone else gets this feeling. It doesn't happen that often, maybe once every month or so. Usually, it happens when I'm in a relatively strange environment, like outside or in class. I don't think it's ever happened while sitting at home. It sometimes happens spontaneously, but tends to occur when I actively gain a strong awareness of my surroundings. It's hard to explain, but I sort of say to myself, "I'm here, right now, in this room. This is reality, these objects are real." It's similar to how some people do reality checks. I can't induce this feeling whenever I want, though. It happens when I'm not expecting it.
The feeling itself is also difficult to explain. It's a feeling that I'm not really here, an inability to grasp that everything around me is real and I'm really doing whatever I'm doing, like I'm dreaming or something. It feels like I've been watching a movie without paying much attention and then realize I'm really a character in it, but it doesn't feel like I am, and I can't help but remain detached. It feels distinct from any other experience, and I don't think anyone who hasn't experienced it will be able to understand it. It lasts for only a few seconds.
I used to think that everyone got this, and that this was what people called "de ja vu". But I've always heard de ja vu described as a feeling that the current circumstances have happened before. This feeling doesn't involve that.