Meditation 7.64-65
64. In the case of every pain be ready with the reflection that it is not an evil, and does not injure the intelligence at the helm; for it does not destroy it, in so far as the soul is reasonable and social. In the case of most pains, however, the saying of Epicurus should help you: 'Pain is neither intolerable nor continuing, provided you remember its limits and do not let your imagination add to it'. Remember, too, that many disagreeable feelings are identical with pain, and yet we do not perceive that they are; drowsiness, for example, and extreme heat, and loss of appetite. Whenever, then, you are disgusted in one or other of these ways, say to yourself: 'you are giving in to pain'.
65. See that you do not feel to the inhuman what they feel to mankind.