Ideally capping of tooth should follow root canal treatment immediately as it strengthens the tooth. But if for some reason you cannot get it done immediately, try not to eat from that side especially hard foods like nuts etc. As the forces placed on root canal tooth can fracture the tooth. Especially if it is the back tooth i.e molar. So if you got your filling done in august..it is high time you get it capped to increase its life and the money and time spend on root canal to save the tooth doesn't get wasted.