The speaker begins by addressing the god of Love. Based on the speaker’s description of him, we can safely assume that this god is Cupid. Still, because the speaker calls him Love, we’ll call him Love too. The speaker says that Love has tricked him by making his eyes unable to tell what they’re looking at. More specifically, he says that his eyes are so totally messed up that they look at the worst thing in the world and think it’s the best thing.
The sonnet’s opening insult is pretty messed up, if you ask us. But then the speaker takes things further—he isn’t done complaining about how badly his eyes have misled him. Now, he says that his eyes have made him fall in love with the world’s biggest slut. How do we know he’s actually in love with her? Because now the speaker brings in not just his "eyes," but his "heart’s judgment" as well. Who does he blame for all this? Why Love, of course—well, at least at first.
Now that he’s really pissed, the speaker starts lashing out at other stuff, like his eyes and his heart. He vents his anger by asking some rhetorical questions about why everything has to be so totally awful. Then, he rounds off the sonnet with a couplet complaining, once again, about how his heart and eyes have deceived him. But he doesn’t end the poem without dishing out some last choice morsels of abuse for his lady-love. This time he calls her a "false plague." ‘Nuf said.