I obviously can't say where your poor concentration stems from, but it sounds like anxiety could certainly be exacerbating it. Sleep could as well. Maybe that's why he wanted to treat the sleep and anxiety first. I mean, it's one thing to treat the underlying cause, but if other things affect concentration too, those things ultimately must be treated as well. So maybe he's just taking things one step at a time.

It sucks that your concentration isn't getting any better, but maybe it will be with the new anxiety and sleep meds. And once the anxiety and sleep are improved, maybe he'll be able to pin down the exact cause of the poor concentration issues and be able to treat those issues as well.

Just my guess.