Suggest Treatment For Amenorrhea

im 21 years old and havnt had my periods since the last 8 months.before that i was on a 3 month estrogen pill course..this problem of amenorrhea started 2 years ago when i lost 30 kgs and was dieting alot.i got way underweight.now i have gained my normal weight and eating much better..i took progesterone (primolut n) 3 months ago for breakthrough bleeding but that didnt happen.i took hormone tests twice..TSH,testesterone,estrogen,LH..etc..and they were normal..my ultrasound was normal as well..What should i do now.?..should i take primolut n again..?..do help..