The “Otzar Dinim u’Minhagim of Eisenstein explains the history and use of the secular year and why it is permitted, though he does not specifically mention the date of Jan. 1. See page 240, under “Minyan Hashanim”.
In regards to the OP, it should be noted that tragedies occur and always have. Relatively speaking, we the Jews have never had it as good as we do now. It is cause for thanks, and not for anguish.