Well let me say first that i dont think your a horrible person !
I would just caution you though that "weed" supposedly stays in the system for at least 30 days i hear. ( havent tested this myself, but used plenty) Anyway, usually here in the US when a baby is born they do run drug screens (however i dont know if they have to have a particular reason to do this or if its standard) and if a baby tests positive they will remove the child from the home , because of child endangerment as well as charge the parent. So if i were you , i think i would get on the ball and find out the answers to loads of legal type questions , before i was in too much hot water legally. Remember, with babies anything can happen and this child could come at any time , not necessarily close to the due date.
I will be thinking of you . I know how hard it is to get clean and stay that way !