Since you must follow a doctor's advice,
Even when stricken by ordinary illness,
What need is there to mention those who are constantly stricken
With the illness of so many faults, attachment and the like?

taken from Shantideva's Engaging in the Bodhisattva Deeds

As he says, I've been sick for a long time with the illness of the afflictions such as attachment - an illness that is long-lasting, intractable, and causes strong suffering. Therefore, I must recognise this to be my situation. Ga-ma-pa said that if we were not in fact sick, then meditating on our sick condition would be misguided. However, stricken with the virulent and chronic disease of the three mental poisons (attachment, hostility and ignorance), we are extremely sick, but we are completely unaware that we are ill.