The speaker is trying to recover from something that has left them hating how they look and how they see themselves. The poem never names it, but the sickness, the cravings, and the obsession with being "so damn pretty" suggest a struggle with body image, possibly tied to disordered habits. That is an inference from the text rather than something stated.
What stands out is how unsteady the progress feels. The speaker keeps saying "I'm better now," yet quickly admits the urge is still there and the sickness "finds its way back." The shaky, repeated "think and think and think" shows a mind that can't switch off, while the physical details, the shake and the heat followed by a chill, make the pull feel bodily. The ending is the saddest part. The mirror shows a "familiar stranger," and when asked if she feels pretty, the answer is a flat "No, of course not." The mood is tired, honest, and quietly painful, with a thin thread of hope.