You're fine. The pull date on the carton of milk is for the convenience of the grocer, not because the health department has come along and deemed all milk to go bad at that point. If it is not sour it is fine. In fact, even if it were a little sour tasting, as long as it had been kept refrigerated, it would probably be safe to drink from a bacterial point of view, it would just taste bad because it had gotten old.