F sharp minor has F# G# A B C# D E and finally ending on F# again I know chord progressions follow as Major minor minor major major minor diminished But my g# minor triad goes G# B D# but D sharp doesn’t exist in the f sharp minor scale so what am i doing wrong?
The chord pattern you've described — major, minor, minor, major, major, minor, diminished — applies to major scales. The pattern for (natural) minor scales is minor, diminished, major, minor, minor, major, major.
So, yes, triads within a key signature are built following the key signature, with the exceptions @Tim noted regarding melodic and harmonic minor.
For a complete listing of minor-scale triads given the different types of minor scales, see Triads derived from the different types of minor scales.
Caught out by the fact that there are several different minor scales!
There are the natural, harmonic and melodic minors. And chords are different depending on which is used. In fact, in F♯ minor, the notes are F♯, G♯, A, B, C♯, D, D♯, E, E♯,(yes, E♯, not F), when all three scales are included. So there's your elusive D♯!
D♯ belongs to the rising melodic minor scale in Classical terms; in the melodic minor scale in jazz terms. The scale you referenced is the natural minor.
So - simple answer - NO. The key signature for minor keys is somewhat misleading - only specifically referring to the notes found in the relative natural minor.