I was told the same. Wouldn't conceive unless I lost weight. I was put on metformin for my pcos in march and I conceived in may without losing weight. Since I found out I've lost about 12 lbs and haven't gained. I'm now 20 weeks and expecting a boy in Feb.
It took me 4 1/2 years to conciev with pcos. I lost 30 lbs and now I'm having a girl on Feb 10th
I was told the same thing 10 yrs ago and I have had twins with fertility now 10 yrs later after being DX with Intercitial cytitis of the bladder and started getting treated for my bladder I no longer have PCOS and started getting regular menstral cycle and I'm now 20 weeks pregnant! My bladder issues actually caused my period to be abnormal until now!
A lot of women lose weight in there first trimester so don't worries just yet keep track and if you notice your stedaly loseing instead of lvl out I would def tell your doc