Lyke as a ship that through the Ocean wyde,
By conduct of some star doth make her way,
Whenas a storme hath dimd her trusty guyde,
Out of her course doth wander far astray: (lines 1-4)
A ship traveling through a large ocean with no land in sight uses the stars to guide its way, but when stormy clouds block the star's light the ship will stray far from its course.
The "her" mentioned in this stanza is referring to the ship; in the English language most (if not all) modes of transportation are described with feminine pronouns. In this analogy, Spenser would be the ship that has gone off course, because his beloved's light is no longer shining on him. A storm is a clever way to describe an argument, because arguments can be described as being dark, angry, heated, wet (meaning crying), and other such adjectives. Astrology plays a big part in this poem and in navigation. Before the time of GPS's all you had to guide your way were compasses and the constellations. The brightest star is the North Star; however, he is not referring to that star in this poem. Instead he is referring to Ursa Major (a.k.a. Great Bear), which contains the Big Dipper.
So I whose star, that wont* with her bright ray
Me to direct, with cloudes is overcast,
Doe wander now in darknesse and dismay,
Through hidden perils round about me plast**. (5-8)
Now I wander around in the darkness, because his guiding light has been concealed by the dark clouds of the storm. Without his light he is left vulnerable to the hidden dangers surrounding him.
The storm has left him without his beloved to guide him. He misses her bright ray, which can be interpreted as he misses her beautiful soul, wit, personality, or any other such personality trait. He is consumed with sadness that he has lost his way, and is left defenseless.
Yet hope I well, that when this storme is past
My Helice the lodestar* of my lyfe
Will shine again, and looke on me at last,
With lovely light to cleare my cloudy grief. (9-12)
*a star that leads or guides; usually refers to the North Star
I hope that when this storm passes my beloved's light will shine upon me again, and guide me back to port (or her), so that they can be together once again.
Helice, also known as Callisto, is a wood-nymph turned into Ursa Major. In Edith Hamiliton's Mythology, the tale is as follows: "she was the daughter of Lycaon, a king of Arcadia who had been changed into a wolf because of his wickedness. He had set human flesh on the table for Zeus when the god was his guest. His punishment was deserved, but his daughter suffered as terribly as he and she was innocent of all wrong. Zeus saw her hunting in the train of Artemis and fell in love with her. Hera, furiously angry, turned the maiden into a bear after son was born. When the boy was grown and out hunting, the goddess brought Callisto before him, intending to have him shoot his mother, in ignorance, of course. But Zeus snatched the bear away and placed her among the stars, where she is called the Great Bear. Later, her son Arcas was placed beside her and called the Lesser Bear. Hera, enraged at this honor to her rival, persuaded the God of the Sea to forbid the Bears to descent into the ocean like the other stars. They alone of the constellations never set below the horizon" (305).
An alternate version of this story can be found in Hans Biedermann's Dictionary of Symbolism: "the Arcadian princess Callisto ("the most beautiful"..., who while a servant of Artemis was made pregnant by Zeus, whereupon Artemis turned her into a bear. She gave birth to a perfectly formed human son, Arcas, who later felt threatened by his ursine mother. Lest one should kill the other, Zeus transported mother and son into the heavens: Zeus' jealous wife Hera, determined to prevent Calisto from ever being able to refresh herself by bathing in the sea, placed her (as Ursa Major) among the circumpolar stars, which never set; Arcas lives on the constellation Bootes" (33).
In secret sorow and sad pensivenesse. (13-14)
These last two lines are known as the rhyming couplet, which functions as a way to sum up the entire poem in as few words as possible. Spenser is telling his beloved that until she forgives him, he will wander aimlessly all alone, thinking sorrowful thoughts.
Spenser, Edmund. "Amoretti: Sonnet 34." The Norton Anthology of English Literature: The Sixteenth Century/ The Early seventeenth Century New York: Norton, 2006. 902-4.