A rant and some advice please

I've recently been diagnosed with PCOS and informed about insulin resistance, the side effect of being tired all the time etc... The thing is, I went to the doctor about all of these when I was a teenager. My weight being unproportional to what I was eating - you need to exercise more and eat less. Losing my hair - eh it happens. Being tired all the time - sometimes I'd come home from school, be asleep by 5, wake up at 11 and eat the dinner saved for me, be asleep again within the hour and then wake up for school the next day at half 7... That's not normal! The doctor said ooh that's TATT syndrome - we got excited thinking oooh we're going to get answers. Nope, tired all the time, sometimes you just need a nap.

How do you stop being bitter? Like I'm now SEVERELY overweight - was doing gym classes 3 times a day, 6 days a week and I still couldn't lose more than a stone.

And now it turns out you have to eat completely differently with PCOS because of the insulin resistance. But everytime I look at the reviews for books about it they're always mixed and I just don't know where to start on figuring out what to do and what I should be eating etc.

Does anyone have any books or sources they'd recommend to just understand what to do? Or just explains everything with why? I just want some help understanding.

I know it's not treatable and you can only try and eleviate the symptoms, I just can't figure out what to read or where to start. I'm so confused, and let's be honest, upset. Any advice or recommendations would be amazing. Thank you :)