The poem starts with a harsh, almost physical image: something "angry as a noon toothache." A toothache is a constant, throbbing pain you can't ignore, and the word "noon" puts it in the brightest, most exposed part of the day. The words "raw and alone" could describe the seashore, the speaker, or both at once. That blur seems to be the point. The landscape and the person feel like the same wounded thing.
Then the poem shifts. The sea "books a ticket / to my sleep," as though it were a traveler planning a trip into the speaker's mind. The pain and loneliness of the daytime shore don't stay behind. They follow the speaker into rest, where we'd expect peace.
The mood is uneasy and bare. The title suggests a place that has become emotionally extreme, and the short lines leave a lot of silence around the words. Judging by the imagery, the speaker can't escape what the sea stirs up.