Chord Progressions

G: G B D D#maj7: D# G A# D A#: A# D F D7: D F# A C

None of these chords share a key, since G Major only has an F# and not a D# or an A# (the last of which would be written as Bb in a minor key.) However, I see a few trails that keep the progression solid: 1: G > G > F > F > then it loops; it's a climb from the b7 to the subtonic to the tonic in a satisfying resolution 2: G > D > D > D... a simple I V I loop 3: D is an ostinato and since it is the V it keeps you in suspense, but also the D > D# > D > C dances around that to make it interesting 4: B > A# > A# > A... between the third and the ninth almost like a I V I 5: This is in no particular key, but jumping from G to D is boring, so they added tension with the bVI which invokes a spacey or nostalgic feeling, at least for my ears; also, A# to D# is a fourth like D to G so it doesn't sound super jarring.

I hope that makes sense.

Edit: The shakiness can be derived from the unstable key center, to allude to the track title. The lyrics depict a character who has just gone through a breakup I presume, so they feel "blue" like a blue note doesn't fit in the key.