Here's a short thought and a practical lesson we can take from today's fast day.
We fasted because the tzaddik Gedalia was killed on this day. He was warned beforehand that someone was planning to kill him but he didn't believe the Lashon Hara nor did he investigate to see if there was any truth to it.
We learn from here that there are times to ask questions, to see if something negative we heard is true-in order to protect ourselves. We can't have an "absolutely no Lashon Hara" policy.
Extremes are not good; everything must be done in moderation.
Maybe this day comes right after Rosh Hashana, when we start to accept new changes upon ourselves so we can be aware: STOP! Don't take too much upon yourself. Do good, make changes, but don't go to crazy extremes or you may end up hurt in the end!
Have a meaningful next few days of slow, gradual changes!