E|--------------------------|
B|---1----------1-----------|
G|---------2---------2------|
D|--------------------------|
A|---0----------------------|
E|--------------------------|
r|---I---II----III--IV------|
(well, that's not a mistake of tabbing, you really hit the string 'between' the 
steps, not on the beat actually)
So it goes:
E|--Th| e main riff--
     Am             C              G                Am 
E|----------------------------------------------------------------|
B|---1-----1--------1------1-------0------0---------1-------------|
G|-------2---2-----------0---0----------0---0---------------------|
D|----------------------------------------------------------------|
A|---0--------------3-------------------------------0-------------|
E|---------------------------------3------------------------------|

And for the chorus it's just the same but with a little variations, I believe that 
you can easily figure it out by yourself.

Am         C         G       Am
I'm not myself when you're around
Am         C             G    Am     
I'm not myself standing in a crowd
Am         C          G          Am
I'm not myself and I don't know how
Am         C       G          Am
I'm not myself, myself right now

F     C               G       Am
Jesus Christ will you look at me
F          C          G        Am   
Don't know who I'm supposed to be
F            C               G       Am
Don't really know if I should give a damn
     F                           G  
When you're around, I don't know who I am

Am         C         G      Am
I'm not myself when you go quiet
Am         C        G        Am
I'm not myself all alone at night
Am         C              G       Am
I'm not myself don't know who to call
Am         C       G  
I'm not myself at all

F     C               G       Am
Jesus Christ will you look at me
F          C          G        Am   
Don't know who I'm supposed to be
F            C               G       Am 
Don't really know if I should give a damn
     F                           G  
When you're around, I don't know who I am

         F                   Am
I always wished that I could find
           F            Am
Someone as beautiful as you
           F            Am        C             G 
But in the process I forgot that I was special too

Am         C         G       Am
I'm not myself when you're around
(I'm not myself when you go quiet)
Am         C        G        Am
I'm not myself all alone at night
(I'm not myself standing in a crowd)
Am         C          G          Am
I'm not myself and I don't know how
Am         C       G          Am
I'm not myself, myself right now
(Don't know what I believe)

F     C               G       Am
Jesus Christ will you look at me
F          C          G        Am   
Don't know who I'm supposed to be
F            C               G       Am
Don't really know if I should give a damn
     F                           G  
When you're around, I don't know who I am

         F                   Am
I always wished that I could find
           F            Am
Someone as beautiful as you
           F            Am        C             G 
But in the process I forgot that I was special too

         F                   Am
I always wished that I could find
           F           Am
Someone as talented as you
           F            Am
But in the process I forgot
     C             G       C    
That I was just as good as you