Wonderful. Absolutely wonderful. A stunning poem. The second verse cuts through my heart like a poetic shock. I am hooked after that. What I really love about this poem is it's sense of vulnerability and mental instability. You can get into the narrator's state of mind immediately and you forget yourself. You can feel the sorrow of this person's conflicted heart.
What threw me off was when you included "fuck this" at verse 3. It didn't feel like it fit the whole poem. Maybe if you omit it and let the "I won't let them hurt you again." by itself, maybe it would have more impact.
The absolute best thing about this poem is the fact that you hear/read the thought pattern of the narrator, and feel as though you are in their shoes. I love poems that allow you to almost forget about yourself and become another person for a moment. The little lines such as "fuck this", "i am pathetic" and "i didn't think i would miss you" further reinforce the fact that you are reading somebody else's thoughts and they additionally carry so much weight throughout the piece.
Lastly, I love absolutely love the ending of this poem! The repetition of "i won't." and then the single "too late." right at the very end continues with the thought-pattern-style of the piece. It is as though the narrator is trying to convince themselves to do the opposite or changing their mind. I really love poems like this!