Klirrendem Kopf literally translates to "clanking head," which is a vivid and somewhat unusual image in German. While "Kopf" means head, "klirrend" typically describes a clanking or rattling sound, like glass or metal.
In this context, it's used metaphorically to describe a throbbing headache or a mind that feels disoriented and noisy, perhaps from a hangover or emotional distress. It's a more evocative way of saying someone woke up with a bad headache, making it an interesting and memorable phrase.
Lea's "Welt" is a really touching song about being there for someone when their world feels like it's falling apart. It starts with a vivid picture of someone waking up to a really tough day: "Mit klirrendem Kopf wurdest du wach, die Wohnung ist kalt" (You woke up with a pounding head, the apartment is cold), and everything just feels wrong. The lyrics describe a sense of deep sadness and isolation, where the person feels like they "will hier nicht mehr sein, doch weißt nicht, wohin" (don't want to be here anymore, but don't know where to go).
But then, the song shifts to a powerful message of support. The singer comes in, saying "ich lasse mich neben dich fallen, du bist nicht allein" (I'll drop down beside you, you are not alone). The core of the song is this beautiful promise: "Ich halt' für dich die Welt zusammen, wenn sie über dir einbricht" (I'll hold the world together for you, when it collapses over you). It's about offering comfort and strength until the person feels whole again, even when they can only "Nebel sehen" (see fog) and think the bad feelings will last forever. It's a truly comforting anthem for anyone going through a hard time.