https://lineblog.me/uematsunobuo/archives/13199762.html

I hope this is just a case of being overworked and isn't indicative of something more serious.

He mentions being ill on different occasions this year in the Japanese message (the rest is basically the same as the English). I can see how all the touring in addition to composing would take its toll. Here's hoping after a bit of rest he'll be back to his chipper old self.