rock bottom

Short definition from Wiktionary

Noun

1. 1
   The very lowest possible level.
2. 2
   The lowest possible state in one’s life, whether mentally, socially, or otherwise; often, a period of extreme mental stress, homelessness, or rejection by all friends and family.
3. 3
   Alternative form of rock bottom.

Verb

1. 1
   To fall to the lowest possible level.