what emotions do Duke Orsino feel as the play begins, and what is causing those feelings?

Count Orsino of Illyria is introduced; he laments that he is lovesick, and wishes that "if music be the food of love," he could kill his unrequited love through an overdose of music. His servant, Curio, asks Orsino if he will go and hunt; Orsino answers with another lovelorn reply, about how his love for the Lady Olivia has been tearing him apart.