By deciding not to declare war after gravely insulting the Jin emperor, you have set your people up for ruin. The emperor pays other steppe tribes to begin raids against yours as retribution. After the declaration that there would be no war at the karultai, your armies are not prepared for these attacks, and your tribe is overran.
You chose a non-historical decision! In real life, Genghis Khan had already planned to declare war long before this karultai. Read more about how your decisions differed here.