Hello Feeling sick, tiredness, dizziness, bad belly , excessive hunger , these symptoms may be due to these reasons , these include : 1 Hyper acidity , as in this age group ( 18 yrs) , this is most common cause. Try raising the head of your bed about 4 inches with blocks. It also might to help to avoid eating or drinking for 2 hours before you lie down. To control stomach acid one should not eat chocolates , spicy , greasy , oily foods. Take some antacid but if symptoms are severe take pantaprazole -D as it will control belly pain, dizziness . 2 Anemia may be the next reason ( if profuse bleeding at time of period ) . Diagnosis can be confirmed by examination of hemoglobin. 3 Worm infestation may be the another reason . Get in stool examination for confirmation. However , there are so many other reasons of such symptoms so consult a physician and get his opinion.