急にやせだしました。

urgent; sudden; abrupt; sharp; steep; precipitous; rapid; swift; fast; emergency; crisis; hurrying; haste; (in gagaku or noh) end of a song

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to become thin; to lose weight; to reduce (one's) weight; to slim; to be barren; to be infertile; to be sterile