Tisha B'av is a time to face the natural consequences of our actions

The book of Eichah was written as a prophecy not as history. It was written to warn us about what happens when we stray from Hashem's path. While Hashem is full of love and compassion for us there are consequences to our actions. Tisha B'av is a day when we focus on the negative consequences of negative actions. Hashem wants us to do Teshuva and return from our aveiros. Hashem does not want to punish us. Hashem want to fill our lives with Brachah but if we do not do Teshuva we will face horrible consequenes.
From the Shiur "Tisha B'av-connecting to Kinos" by Rav Yitzchak Berkowitz on Aish Audio.