The speaker of "Tulips" is going through a tough time. For one thing, she's just been through surgery, which can be pretty painful and traumatic. It's not just that, though. You can tell from the way she tells us about her world that something still isn't right, even after the surgery. She's suffering from something more mysterious, something more dark and internal. But what? Seriously, we're asking! Your theory is as good as ours.
This is a poem about how the body and mind suffer together. You simply can't separate mental and physical pain.
Over the course of the poem, the speaker proceeds from dreaming about peace in the midst of suffering to actually feeling it. She's not completely better, but her outlook has improved, at least for a moment.