Here the speaker describes a kind of emotional numbness that feels almost physical. Feeling is "slipping away" and "dripping down the drain," and the image of lidocaine, an anaesthetic used to deaden pain at a wound, gives the idea a clinical edge. The twist is that the numbing isn't aimed at an injury. It's aimed at the speaker: "instead of my wounds / It's me."
The middle of the poem sits in exhaustion. The speaker is awake but too drained to act, and too tired even to sleep. Then the mood shifts. The speaker imagines running through fields, forests, swamps and marshes, with wildflowers and insects "flying like shooting stars." These images are bright and alive, and they contrast sharply with the flat bedroom scene before them.
The ending is plain and direct. The speaker wants to be free of "shackles" and to feel more than "discomfort / And apathy." The overall mood is weary and heavy, but a quiet longing for life runs underneath it.