Sounds like you had Rocky Mountain Spotted Fever, I had the same symptoms and my doctor immediately put me on antibiotics. A few weeks later my blood tests came back with traces amounts of RMSF. It was the worst I've ever felt.
I rather spend 4 hours doing a project where I can demonstrate my value (architecture, clean code, design patterns, etc) than spending the same 4 hours solving questions on a whiteboard.
Hell, most of the value I bring as a senior is well outside the realm of coding.