Hello and first of all apologies in advance for potentially sounding weird as English isn't my first language.

I am a 20 year old male with a history of atypical depression and social anxiety but my treatment so far has been limited. The only medication I'm occasionally taking a small dose of insidon to help me sleep.

So much regarding the general situation.

The reason why I'm here: I have been experiencing some really freaky things and I don't know what the hell they are and what's going on with me. The are basically "apparitions", sort of demon like humanoid creatures that are lurking in my room staring at me. I know they are not real, I know they are not there, and I can't even actually SEE them. I just FEEL like I can see them. It's like for example I'm sitting at my desk and I get this feeling that there's someone or something in the room with me and I can exactly describe what that being looks like even though I can't see it. And I know that if I would turn around nothing would be there. While at the same time I am like paralysed and too terrified to turn around and check.

I don't know what the hell is going on. I'm scared that this might be a sign of something like psychosis but if I were psychotic I wouldn't be aware of the fact that these things aren't real, right? I don't know an awful lot about psychosis so I don't know if that's actually true or a misconception.
Additionally, I am aware that demon like creature have a certain religious connotation but I was raised in an atheist household and have no religious belief, so it's nothing like that either.

Please, if someone knows what is going on with my brain, please tell me. I'm freaking out.