Lose your terminal session? Did your VPN drop? Did you have a bunch of work you were doing in your bash session and because you lost connection, your session closed uncleanly and you wanted to retrieve your command history?
Yeah. Sucks, huh?
Here's a simple fix:
insert the following in your ~/.bashrc :
# vi ~/.bashrc
export PROMPT_COMMAND='history -a'
Now your commands will "flush" to the history file immediately.