This song is pretty easy. 

Intro: Dm C Dm C Dm C Dm C

Dm       C               Dm      C       Dm     C     Dm     C 
Now and then I think of when we were together
 Dm            C                Dm    C        Dm     C     Dm    C
Like when you said you felt so happy you could die
 Dm     C                   Dm      C 
Told myself that you were right for me
 Dm            C              Dm    C 
But felt so lonely in your company
 Dm           C                Dm      C      Dm     C     Dm     C
But that was love and it's an ache I still remember

Instrumental: Dm C Dm C Dm C Dm C

 Dm             C            Dm    C        Dm     C     Dm     C 
You can get addicted to a certain kind of sadness
 Dm        C             Dm    C         Dm     C     Dm     C 
Like resignation to the end, always the end
Dm           C                 Dm         C 
So when we found that we could not make sense
 Dm       C                  Dm         C 
Well you said that we would still be friends
 Dm        C               Dm       C       Dm     C     Dm     C
But I'll admit that I was glad that it was over

Chorus:
Dm        C            Bb      C 
But you didn't have to cut me off
 Dm       C               Bb             C         Dm 
Make out like it never happened and that we were nothing
    C             Bb        C 
And I don't even need your love
         Dm                C               Bb        C 
But you treat me like a stranger and that feels so rough
 Dm      C             Bb       C 
No you didn't have to stoop so low
 Dm          C                   Bb               C           Dm 
Have your friends collect your records and then change your number
    C                 Bb         C 
I guess that I don't need that though
Dm                 C             Bb      C 
Now you're just somebody that I used to know

Instrumental: Dm C Dm C Dm C Dm C  

Dm       C              Dm                  C         Dm     C     Dm     C     
Now and then I think of all the times you screwed me over
Dm            C               Dm              C        Dm     C     Dm     C
But had me believing it was always something that I'd done
Dm  C              Bb        C 
But I don't wanna live that way
  Dm     C          Bb       C 
Reading into every word you say
Dm   C                   Bb    C 
You said that you could let it go
        Dm                C            Bb              C       Dm 
And I wouldn't catch you hung up on somebody that you used to know

Chorus:
Dm        C            Bb      C 
But you didn't have to cut me off
Dm        C              Bb              C         Dm 
Make out like it never happened and that we were nothing
    C             Bb        C 
And I don't even need your love
         Dm                C               Bb        C 
But you treat me like a stranger and that feels so rough
Dm       C             Bb       C 
No you didn't have to stoop so low
Dm          C                    Bb               C           Dm 
Have your friends collect your records and then change your number
    C                 Bb         C 
I guess that I don't need that though
Dm                 C             Bb      C 
Now you're just somebody that I used to know


   Dm     C 
Somebody
    Bb      C 
(I used to know)
   Dm     C 
Somebody
         Bb      C 
(That I used to know)
   Dm     C 
Somebody 
    Bb      C 
(I used to know)
Dm               C             Bb      C 
Now your just somebody that I used to know 

Outro: Dm C Dm C Dm C Dm C

Hope you like it!