Thanks for the query.
Usually chronic alcoholism
causes more harm to the baby than acute heavy drinking.
So you better consult gynecologist confirm your pregnancy
and start taking folic acid
and multi-vitamin tablets.
After two weeks go for ultrasound
once which can detect the development of the baby.
Routine regular antenatal checkups are important. And one TIFFA scan at around 20 weeks will rule out any possibility of anomalies in the baby.