It's a pretty long story, but please hear me out:
I was diagnosed with PCOS 2 years ago and after losing 4kg I got my period back. 1 year later I gained 2kg and my periods stopped. I was prescribed some hormones (Provera) in January this year and I got my period then.
In February I started a new diet plan (having 5/6 small meals per day instead of 3 big ones and reducing the amount of carbs consumed) to lose weight. I lost 2 within the first two weeks and it remained that way. I also had my period that month.
Now in the beginning of March, I got stressed out due to various personal reasons. Starting from 3 weeks ago I began to feel tired and dizzy all the time and a slight pain/discomfort in the left side of my chest. I first lost 1 kg overnight after receiving some bad news and gradually another 1 kg over last week.
I've lost weight because stress before, but never this fast. Worst of all, I still haven't gotten my period this month and it's later than usual. Is this because of my diet, my being stressed, or any other possible illnesses that I'm unaware of? I'm almost 19 and my BMI is now 20.6.