While perfection is, well, perfect, there's no need to freak out if you don't quite finish cleaning house before egg and sperm meet. If you have a glass of wine (or three) during week one of your pregnancy, there's no need to worry. After all, you're not actually pregnant.
Another thing that needn't freak you out? If it takes you a while to get to week one in the first place. It's perfectly normal for conception to take more than one try.
In fact, at this point, don't worry at all. It's easier said than done, but try to relax. You're gearing up for what will ultimately feel like a marathon, so pace yourself. There will be plenty to keep you worrying later on. Like whether or not you'll poop during delivery. (You probably will.)