Almost every line here is a question, and none of them gets an answer. The speaker keeps asking "when?", and the repetition makes it sound like someone who has been waiting a long time and is running out of patience. Something is stuck in their head, and the poem never says what it is. "When is it going to leave my head?" suggests a thought, memory, or feeling that won't let go, though we can only guess at its source.
What the speaker wants is surprisingly simple: to be "free," to be "me," to be "alive again," even to be "regular." That last word stings. After all the bigger hopes, they settle for ordinary. The title, "Tough," adds a twist, since the speaker seems tired of having to be the strong one and wants a turn at being okay instead.
The mood is weary, raw, and a little desperate. The short lines feel like quick, tired breaths, and the lack of resolution leaves the reader sitting in the same uncertainty as the speaker.