My Love Is As a Fever (Sonnet 147)

My love is as a fever, longing still
For that which longer nurseth the disease;
Feeding on that which doth preserve the ill
The uncertain sickly appetite to please
My reason, the physician to my love
Angry that his prescriptions are not kept
Hath left me, and I desperate now approve
Desire is death, which physic did except
Past cure I am, now Reason is past care
And frantic-mad with evermore unrest;
My thoughts and my discourse as madmen's are
At random from the truth vainly expressed;
For I have sworn thee fair, and thought thee bright
Who art as black as hell, as dark as night