You should consult with a cardiologist regarding the use of antibiotics. The guidelines changed about a year ago, and the results could affect whether you should premedicate (or not). Please give your doctor's office a call.
As for the pot, that's another good question for the doctor. Perhaps you could stop smoking and see how you feel. Regardless, with 3 young children, talk with the doctor to be sure you are doing what's in all of your best interests.