Verb (5-dan, む, intransitive)
1. to feel down; to feel sad; to be depressed; to be in low spirits
まだ落ち込んでるのか。Are you still feeling down?
2. to be in a slump (business, economy, etc.); to be in an unfavourable condition
記録が急激に伸びるどころか、かなり落ち込んでいるようですが。Far from improving rapidly, the records seem to have dropped quite a bit.
3. to fall into (e.g. a hole)
タイヤが溝に落ち込んで、車が動かなくなった。A tire fell into a ditch and the car got stuck.