Sounds like Brain fog... I've had it for 12 yrs... Awful... Still haven't found a cure but rest & keeping my stress level down is helping... I get stressed from pushing myself. Recently diagnosed with CFS but also FM... I go back to the Dr in 3 weeks so hopefully he'll let me know which one... He says FM, his nurse said CFS... I get the impression that he thinks CFS turns into FM. There's also the theory they are the same thing which I believe is pretty accurate.
Anyhow, I went to Dr after Dr trying to find out what is wrong with me. I've had many other symptoms, not just fog... Just got worst over the yrs. Doctors would look at me like I was nuts. I'd get frustrated & wouldn't see a Dr for another yr. I finally had a Dr take me serious recently. She sent me to a Rhumetologist. It was the first time I'd had a Dr take me serious & actually understand what is going on with me! It's a great feeling!
Anyhow, I recommend seeing a Rhumetologist. It's only been 6 months so with their help, your recovery will be quicker.