My obgyn diagnosed my baby with moderate IUGR - I'm 31 weeks along n haven't gained any weight in this pregnancy (infact I lost weight)

I'm on L-arginine supplements but it hasn't helped the baby growth. Baby weighs 1.6 kgs at present, Doppler shows all OK.

Obgyn says they may schedule me for an early delivery if things don't improve in a week's time.

This is my first pregnancy, baby was a surprise but I tried my best.. I'm not sure what I'm doing wrong or what I can do to correct.. could work stress be causing this? anyone who can shed insights on this condition n some helpful advice, I would be SO appreciative! :(