Five short lines carry a whole relationship's worth of feeling. The speaker begins by simply asking to be loved: "love me," then "Please love me." The plea is raw and a little desperate. By the third line the request has shifted. "Please I love you" sounds almost like an argument, as if the speaker hopes that offering love might earn some in return. Then comes "Please let me love you," which asks for much less. Now the speaker only wants permission to give love, not to receive it.
The last line changes everything: "Sorry I loved you." The pleading stops, and what's left is regret, or perhaps an apology for loving someone who didn't want it. It's hard to tell whether the speaker is bitter or just worn out. Either way, the poem moves from hope to resignation. The mood is quiet, vulnerable and sad, and the repeated "please" makes the ending hurt more, because we have heard how hard the speaker tried.