Foggy feeling in my head, what is this?

For the past few months I've been getting this super weird feeling in my head, it's like a pressure or a cloudiness in my thoughts and I can't focus on anything properly, it's stopping me from doing normal tasks and I just constantly feel over stimulated or something.. It's really frustrating I can't get this feeling away it's also making me more clumsy and my memory is getting worse and I kinda feel detached from everything too, like when people are talking I feel like it's not really them talking and I'm having a weird outer body experience. The only time it gets a little better is when I'm in a dark room on my own. I'm only 17 I have no idea what this is.. I don't take any medication and I've never had this intense feeling before, I did have depersonalsation years ago but it feels totally different. I will go to the doctor but just curious what anyone thinks.