I have been through something similar, when facing very tight deadlines. The most recent was in 2012. It was the first project where I had ever worked with Clojure, had ever worked with the JVM, had ever worked with "functional" concepts. I had to learn a great deal in a hurry, and the hours were crazy. I got very sleep.

I developed weird memory issues, in particular about people's names. I could remember details about people -- where I knew them from, what they did, but their names went completely. This included some people who were close to me, so there was a scary feeling of the memory loss being strange and almost like dementia.

I have rarely had to learn so much in such a short amount of time, and for awhile it was literally as if each new thing I learned was pushing something else out of memory, as if my brain was full and I could only learn new things by erasing something else.

Thankfully, the project ended, I got some sleep, and a few months later I felt normal again.