Thanks for your query.Metformin
is safe to be consumed during pregnancy
and is often prescribed to patients with PCOS
Your symptoms could be due to premenstrual symptoms.
With a negative pregnancy test , you are most probably not pregnant.
Please consult a gynecologist as metformin is given to PCOS to regulate metabolic symptoms, and not as an aid to conception.
You might require help of ovulation inducing agents.