Studies have shown that consistent smoking and drinking throughout your pregnancy will cause problems but doing so in very early pregnancy has not reported any long-term ill effects. The placenta doesn't form until week 8 or more so it is doubtful much has even passed to the baby at this point. Good for you for quitting; keep at it and get healthy for your little bean. ;-)
Doubtful. A lot of people smoke cigarettes and drink booze before they find out they are pregnant, quit, and then go on to have healthy normal pregnancies.
Unlikely that anything serious has been done. The important thing is that you quit once you find out that you are pregnant. Good luck with your pregnancy!