Tough times can cause us to get our perspective turned around. I was reminded of this recently as I talked to a fellow-griever—another parent who, like Sue and me, lost a teenage daughter to death suddenly and without warning.
She told me she had been missing her daughter terribly, and she told God she felt as if she were hanging on by her fingernails. Then she felt as if God reminded her that His hand of protection was there to hold her up—that she could let go, and He would catch her.
What does "hanging on by her fingernails" mean?
See: cling on on by fingernails: - Idioms - by the Free Dictionary, Thesaurus and Encyclopedia.
cling on/hang on by your fingernails
if you are clinging on by your fingernails, you are only just managing to avoid danger or failure (usually in continuous tenses)
"We're hanging on by our fingernails and hoping that it rains before we lose our entire crop."
Hope this helps