Yes it is the drug of choice to be taken in the first three months of pregnancy as it will prevent some anomalies in the pregnancy. There is no other option than taking this medicine.

If you r not vomiting now there is no need to continue medicine for vomiting. If nausea is completely stopped then folic acid tablets will be changed to iron and calcium tablets, but it is not urgent. It can be started after 1 month also, in the meantime continue folic acid.