The entire soliloquy is constructed of Hamlet's arguments for and against killing himself. The idea is so repugnant to him that he can only express it impersonally. He doesn't say "Shall I go on living or kill myself?"
Usually Hamlet separates his thoughts of living or dying by the conjunction "or." The passages that represent the ideas of living or dying get longer and longer.
The first antithesis is completed in the first line. But the second begins with "Whether" and continues for two lines. Its antithesis begins "Or to take arms" and takes up most of the next two lines.
Whether 'tis nobler in the mind to sufferHint: the next antithesis has to do with sleeping versus dreaming. There are several more in the passage.
Note that one of the structures that the whole play is built on is: being forced to choose between two actions, both of which have horrid consequences. Hamlet, in this speech, is trying to choose between a wretched life and fearful death. Claudius must choose between keeping Gertrude as his wife and enduring a guilty conscience, or salving his conscience by giving up the person he loves most. Similar predicaments confront Gertrude, Ophelia, Laertes, Rosencrantz, Guildenstern, etc.