Short stories is the answer. They do seem to mainly the province of horror and sci-fi but even if that's not a favoured genre(s) it's a way back in. Try Night Shift or Skeleton Crew by Stephen King (give The Mist a miss though, it's not really a 'short' short story). Take it a page at a time, stop reading the minute you start to lose interest, try again 15mins later. Remember it's fun activity not a competitive sport, take all the time you need, the books you want to read are going nowhere :)