I'm curious. Does your native tongue have distinct words for these? Mine is Hindi, which doesn't. Neither does any other language I know. (Except for Sanskrit, arguably. Just about anything can be sandhi-fied (joined) into one word in Sanskrit.)
this week and
this month are used considerably less frequently than today or tonight, as this ngram shows, which might (I said might) explain why the need was not felt for dedicated words to express them.
And I'd be willing to bet that most, if not all, languages don't have these words either. I'm trying to say that English isn't behaving strangely here.
Oh, and I might as well repeat what Marv said. There is no 'language authority'.