Yes, that temperature is WAY too low and will contribute to soil pH problems too. In fact, you have inadvertently accomplished something that is usually a bit difficult- putting a plant in a dormant condition over a long period of time. If you had been watering on a 'normal' schedule, that plant would have died AGES ago.
Get your room temerature up over 70 degrees, and gradually start feeding it a proper grow fertilizer.
READ!!!! The link in my sig is a good place to start.