The rapid and unintentional weight loss makes me think you really need to be checked for Addisons disease.

The best way to check for Addisons is the ACTH stimulation test sometimes called the Cortrosyn/Synacthen test.

Do you have any abnormal skin pigmentation?

Good to get checked out for PCOS too, but rarer than PCOS is a condition called Non Classic Congenital Adrenal Hyperplasia. NCCAH can also be diagnosed during the ACTH stimulation test with the addition of 17-hydroxyprogesterone and the androgens (testosterone, androstenedione and DHEA) in addition to cortisol.

I wish you the best in finding out your problem.