Loss of appetite and altered menstrual cycle can be due to many reasons. One simple reason could be that you are stressed out. Stress also makes you want to smoke more. Please also remember that if you smoke more than your usual, you are bound to lose appetite and may also have nausea
. Rather than worrying about your health and smoking
more, it will be better to consult a doctor and get a check-up done. Most probably, there is nothing seriously wrong with you and you'll get better in a few days.