Just say it's a personal choice not to do those things. Your baby didn't have a choice to be here so you have to do what's best for her from the beginning. Usually when you tell people that they back off. Worked for me anyway. Good luck!
Go with what your doctor says. There are plenty of medical studies that show its bad to smoke and drink when your pregnant. Some people do it and their babies are fine but they are the lucky ones and you don't want to risk your babies health. In the end it's your decision but what you do affects LO and he's the one that has to deal with the consequences good or bad.
I don't want to sound harsh, but girl, why do you have friends who would tell you to do those things while pregnant?! That seems crazy to me. I am not trying to be "holier than thou" or anything I just think that it would be best to not surround yourself with those people or have them around your sweet babe.
Personally I would put space between myself and said friends- I like to surround myself with people who want good for me, as I want what's best for them. If someone was giving my such awful advice they clearly are either clueless or don't really care. IMO
Re: bad intentions