Nice reflection. Thank you. Barthes made the transition from structuralism to poststructrualism with S/Z. He concludes that his structuralist analysis of "Sarrasine", with his notorious 561 "lexias" or units of reading and his 5 codes of analysis, is ultimately arbitrary - meaning is plural, indeterminate, diffuse. You can see something of Derrida here.
Please reply to this text. But I read that you Brian Dillon lived many years with health anxiety...I assume you eventually managed to control your anxiety so that it didn't destroy your enjoyment of life and your passions....which appears to be literature..