that's easy,  there are four different chords, D Bm F#m throughout the whole son 
then C#m just before the final chorus.

            D                                         
Thinking about the time we shared
    Bm
And how I wasn't there
       F#m           
It hurt me, these people overworked me



keep on with this chords throughout the song then at the end:


   D
S.O.S. to your ears
        Bm                                    C#m
The only thing I ever feared was this day

And having to say


that's all, for an acoustic version this sounds good, hope you'll enjoy it
cheers