As far as I know you can just go into a walk in clinic and get a prescription. That worked for me while I lived in Canada. But here in Russia I just ordered meto from online pharmacy which was delivered to the closest pharmacy available, no prescription required to order online, but you are supposed to show it at the pharmacy when you pick it up. The thing is no one here asks for that unless it's some serious drug. So maybe try doing it the same way and you might get lucky? If they ask you for it just try making up a story that you lost it or smth like that. Try different pharmacies as well.