How To Regain The Period Cycle?

i have had an ED for 4 years and have now reached 130lbs. I am 5'6 and my lowest weight was 109 before i got help. my nutritionalist says i need to gain another 10 lbs so i get my period back, and if i dont get it then she says i need to gain another 5. i dont want to gain any more weight i am scared. will the period just come back on its own after such a long time wiwthout it (4 years)?