Sadness is the whole subject here, and the poem plays with colour to show it. The speaker, "she," is so deep in feeling blue that she can't even "see red," which might point to anger, passion, or perhaps something more energetic that she can no longer reach. Then the poem turns: red is what "left her." Something warm and alive seems to drain out of her, leaving only the blue behind.
The last line, about wishing she could "cry all her blues away," suggests she wants relief but can't find it. Crying would at least release the sadness, and she can't manage even that. The trailing ellipsis leaves the thought hanging, as if she's still stuck there.
The title, "Hues of you," hints that this might be about someone else, a person whose absence or presence colours how she feels, though the poem doesn't say so outright. The mood is quiet, heavy, and numb, a sadness that has run out of ways to express itself.