Romeo seems to be obsessed about loving, if for any reason but to escape the quarreling he sees around his home and family, even sensing upon his return from his walks. For Romeo, to "desire increase", it is the increase in love that he yearns, constantly brooding, walking, and chasing 'this love'. It almost seems that it doesn't matter whom, Juliet or Rosaline, as long as Romeo has a recipient for his love. The sonnet seems to be referring to Romeo, who I don't believe is the narrator. Romeo is being told that he's being hard on himself, the lover. That he is his own enemy. He thinks that his "beauty's rose" may never die, when in fact, the most realistic scenario will be nothing but his heir maybe or maybe not bearing his memory, or even his resemblance. Confused, he has thrown himself in self-induced pressure pit (when you see nothing around you but the walls of that pit, yes my own idea) where he forces himself himself to pretend he's lacking where he truly does not. He's even asked, where are you going with this? "Is Rosaline, that thou didn't love so dear, so soon forsaken? Young men's love then lies not truly in their hearts but in your eyes." Romeo here isn't being true to himself, rather, he is creating his own chase, to eat the worlds due, by the grave and thee, wether or not he decides to slow down and take a breath so we won't have to yet get again, pity the world.