How do we know that Michael is ashamed of what he has done?

From the text:

 "She's gone—to be sure she is—gone with that sailor who bought her, and little Elizabeth-Jane. We walked here, and I had the furmity, and rum in it—and sold her. Yes, that's what's happened and here am I. Now, what am I to do—am I sober enough to walk, I wonder?"