The Question and Answer section for Shakespeare’s Sonnets is a great resource to ask questions, find answers, and discuss the novel.
I think the third quatrain addresses the problem posed by the speaker in the first quatrain. The third quatrain offers a solution to the speaker's problem: he remembers that someone somewhere really loves him and this love is enough to bring him...
I think your best course of action would be to find examples of poems and sonnets in iambic pentameter. Sorry, forum space is meant for short answers only.