The speaker describes the pain of being hurt by words, especially from someone you love, and compares that hurt to being shot. The poem moves through a dark moment: the speaker braces for the blow, seems ready to give up, and goes numb. Then a small hope appears. Maybe the people close to them didn't forget them, but simply failed to notice the signs. The line about humans being selfish isn't an accusation so much as a reminder that this is no reason to stop living.
The speaker is also frustrated with doctors, the "white coats" who poke and prod at a feeling that may not be an illness at all. They don't really know better, but the speaker lets them pretend. What's needed is simple: some love. The mood is tired, raw and quietly sad, and the final image of a recipe missing one ingredient leaves it unresolved, as if the answer is close but still out of reach.