Hello, For The Last 3 Weeks Or So I Have

Hello,
For the last 3 weeks or so I have been feeling very odd. Almost like I'm in my own little world, which I've also described as feeling a bit spaced and very tired no matter how much sleep or rest I get. I have completely lost my appetite which is strange for me, usually a good eater. I've been suffering with really bad headaches, constant thirst and an odd metallic taste in my mouth.
I am unable to get an appointment with my GP for another 2 weeks, I would really appreciate some advice or an idea as to what may be going on with me.
Thank you