You pick another book to read. I find that the most useful way to do this is to take a hard swerve. Last year, I read Greg Egan's Diaspora, which is a super-heady, diamond-hard sci-fi novel that blew my brain apart. I followed it up with W.G. Sebald's The Rings of Saturn, which is pretty much the polar opposite kind of book. I'm not trying to chase the same high, I'm just trying to feel something new.