Drayton begins by scolding himself. "Why do I speak of joy, or write of love," he asks, when his heart is "the very den of horror"? The question is slightly odd, because the poem never speaks of joy at all. The speaker is so far gone that the idea of a love poem seems a joke at his own expense. From the first line, love is a place of punishment rather than sweetness. His soul knows "the pains of Hell," with "all his torments and infernal terror." The verb matters here: to "prove" Hell is to test it, to know it firsthand, so he is reporting what he has undergone rather than borrowing a metaphor. "Den" adds something animal, a lair where something wild lives.
The second quatrain turns from fear to exhaustion. His brain is "dry with weeping," his sighs "spent in uttering my woe." The imagery is all depletion, of liquid and breath used up, until he "want[s] words wherewith to tell my wrong." Here the poem sets a small trap for itself. A man with no words left is still managing fourteen tidy lines, and the sonnet knows it. The claim of speechlessness is part of the performance, a way of saying that his pain is greater than anything language can hold, while using language to say so.
The turn comes at "But." Being unable to speak does not mean being able to stay silent, so he is "distracted in Love's lunacy" and "bedlam-like." Bedlam was a word for a madhouse, so he is picturing himself as an inmate raving. What follows is the real heart of the poem, four lines built on the same pivot, *now… then*. He rails on her hair, then on her eye. He calls her "Goddess," then "thief." He denies her, then confesses her. He curses her, then blesses her. Each line splits at its midpoint into opposites, and the rhythm becomes a pendulum, so the reader feels the swing as well as understanding it.
The vocabulary is worth noticing. "Hell," "Goddess," "confess," "bless" are all religious words, and the speaker keeps shuttling between worship and damnation. "Deny" and "confess" also sound like the language of a trial or a confessional, as though he were both witness and accused. "Thief" is the sharpest word in the sequence. The poem doesn't say what has been stolen, but judging by everything before it, his peace of mind is the likeliest answer. It is also telling that the woman appears only in fragments, "hair" and "eye," the stock features of love poetry. She is hardly a person here, more a surface for his moods to strike against. The poem is less about her than about the weather inside him.
Formally, the sonnet is as orderly as its speaker is not. The rhyme scheme is the Shakespearean ABAB CDCD EFEF GG, and the lines mostly keep a steady iambic beat, five stresses to the line. The two double rhymes, "horror/terror" and "confess her/bless her," each add an extra unstressed syllable. At the start this gives the dread a dragging, falling sound. At the end it has an almost tumbling quality, as though the speaker can't stop himself from adding "her" once more. To a modern ear "lunacy" and "eye" make a looser rhyme, but the pairing still ties madness to the beloved's gaze.
That tension between form and feeling is what makes the poem worth reading. A sonnet's closing couplet usually settles the argument with a neat conclusion or a reversal. Here the couplet simply repeats the swing in a new pair of verbs, and "then again I bless her" suggests the pendulum will go on moving after the poem stops. The ending offers no cure and no wisdom, only a more exact picture of the problem. Drayton gives confusion a clean, balanced shape, and the result feels truthful: anyone who has felt two strong emotions at once toward the same person will recognise the speaker's mind in the way each line cancels itself out.