Around two years ago, I tried devising a language for roughly this purpose. I concluded that it wasn't a worthwhile use of time; devising it is easy, but becoming fluent takes way too much time, especially since there's no corpus (or a very small corpus, if you use something like Lojban).

I write down and regularly review all my ideas, experiences, etc., and I've found it very useful to invent my own words (interspersed in normal English) for concepts that need annoying circumlocutions in normal English. I also use the derivational morphology of Esperanto and my own conlangs.

For an interesting example of a personal language created as a psychological experiment, see gjâ-zym-byn.