Suggest Treatment For Secondary Amenorrhoea

i m a 23 yrs old unmarried women.. i m suffering from secondary amenorrhoea since 4 yrs...my menses are irregular...i hav gained weight after that and my weight is 66kg now.. my height is 5.5. i hav undergone many test such as TFT and USG of abdomen nd pelvis but all my reports are normal...please help me i want to know the diagnosis and treatment for it.