Hi, I Am 23years Old, Unmarried. My Periods Are Missing

Hi, i am 23years old, unmarried. My periods are missing from more than 4months. My weight was increased by 15kgs in past 1year and i have undergone through some mental and emotional pressures in past 6months. I guess my case is Amenorrhea. Can you suggest me some tablets inorder to produce menstruation now. Aside by i have started physical excersies to reduce my weight.