Don’t think about the terrible things in this world but think about the good things Allah has given us. Allah has given us the 10 days of Dhū l-Hijjah to do the things that please Him and for which He blesses us. You may fast all 9 days but the fast of the 8th and 9th days brings the most reward.
And on the 9th recite 1,000 Ikhlas.