Sefer Ha’mitzvos Ha’Katzar (The concise book of mitzvos) By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
Second Section – the Negative Commandments
165. It is a negative commandment “do not act on omens.”
As it states in Vayikra (Leviticus) 19:26, “do not act on basis of omens.” For example, those who say, ‘my bread fell from my mouth,’ or ‘my cane fell from my hand. Therefore, I will not go to such and such a place today.’ This includes one who makes signs for himself like, ‘if such and such will happen to me, then I will do such and such.’ If a person acts on basis of an omen like these, he transgresses this negative commandment.
This applies in all places and at all times, for men and for women.
4. Be kind to yourself. Speaking badly even about yourself is unethical.
הלכות שמירת הלשון 