Right Lads this is a fantastic song but working out the chords by ear is a pain in the 
parts so I've done my best to do all the work for you. This is my first ever tab so bear 
me.

The Cadd9 used is a standard C shape but played with the 3rd fret on the high E string (1st)
The Cadd9 variation is exactly the same except the D string is played open instead of 
second fret
The Am is standard
The Am variation is the same but the B string is played open instead of the first fret
The Em is standard
The Fadd9 is a standard F but instead of fretting the 1st fret you fret the 3rd on the 
E String (1st)
Now the G is a weird one. It's a standard G but the B string is fretted at the 1st fret 
it's keeping the shape of the Fadd9 but the top 2 strings stay as if it were a standard G.
Then its back to the Cadd9
Then G again and then its straight into the verse so your chord bank should look 
like this

Cadd9  (X,3,2,0,1,3)
Cadd9V (X,3,0,0,1,3)
Am     (0,0,2,2,1,0)
AmV    (0,0,2,2,0,0)
Em     (0,2,2,0,0,0)
Fadd9  (0,0,3,2,1,3)
G      (3,2,0,0,1,3)
F      (1,3,3,2,1,1)

Intro: Cadd9 Cadd9(variation) Am Am(variation) 
Fadd9 G Cadd9 G


Cadd9
All this talk of getting old
                Am
It's getting me down my love
                Em              Fadd9
Like a cat in a bag, waiting to drown
     G        Cadd9
This time I'm comin' down
Cadd9
And I hope you're thinking of me
                Am
As you lay down on your side
                    Em
Now the drugs don't work
                   Fadd9
They just make you worse
      G                  Cadd9
But I know I'll see your face again

Now the drugs don't work
They just make you worse
But I know I'll see your face again

But I know I'm on a losing streak
'Cause I passed down my old street
And if you wanna show, then just let me know
And I'll sing in your ear again

Now the drugs don't work
They just make you worse
But I know I'll see your face again
             F    Em               Am
'Cause baby, ooh, if heaven calls, I'm coming, too
              F     Em                 Am
Just like you said, you leave my life, I'm better off dead

All this talk of getting old
It's getting me down my love
Like a cat in a bag, waiting to drown
This time I'm comin' down

Now the drugs don't work
They just make you worse
But I know I'll see your face again

'Cause baby, ooh, if heaven calls, I'm coming, too
Just like you said, you leave my life, I'm better off dead

But if you wanna show, just let me know
And I'll sing in your ear again

Now the drugs don't work
They just make you worse
But I know I'll see your face again

Yeah, I know I'll see your face again
Yeah, I know I'll see your face again
Yeah, I know I'll see your face again
Yeah, I know I'll see your face again

I'm never going down, I'm never coming down
No more, no more, no more, no more, no more
I'm never coming down, I'm never going down
No more, no more, no more, no more, no more
(Repeat and Fade Out)