I spent about a year and a half being dead weight. I was so completely burned after working months of 70 to 90 hour weeks I just couldn't do anything. Things that used to take me an hour to code now took me days. Complete mental block. Luckily I had built up such a good reputation prior I was able to coast and it was a weird project. In a new job / role now and it's better. Only work 40 hours max. Still not back to normal but 75% of the way there.