Hi I Am 22 Years Old. I Have Not Had

Hi I am 22 years old. I have not had a period in over 5 months. I have had bloodwork done and I am not pregnant. I used to have regular periods. I have been losing a lot of weight. As I am always nauseous and vomiting when I eat. I have extreme fatigue. Very dizzy and week. As of now I am hardly able to type whole body is shaky. Very dizzy, nauseous, and extreme fatigue and headache.