This is probably my favorite song... I can relate to it. Anyways, I made this 
totally by ear so I hope y'all like it. First tab :)

       cadd9
Should've kissed you there
           D
I should've held your face
           Em
I should've watched those eyes
          D
Instead of run in place

         G
I should've called you out
         D
I should've said your name
         Em
I should've turned around
         D
I should've looked again

    G        D             Em      C
But oh, I'm staring at the mess I made
(G)     D             Em     C
  I'm staring at the mess I made
(G)     D             Em    C(or alternative Bm)
  I'm staring at the mess I made
        Em        D                   C
As you turn, you take your heart and walk away

     cadd9 
Should've held my ground
          D
I could've been redeemed
            Em
For every second chance
            D
That changed its mind on me

           G
I should've spoken up
           D
I should've proudly claimed
          Em
That oh my head's to blame
          D
For all my hearts mistakes

    G         D            Em      C
But oh, I'm staring at the mess I made
(G)      D            Em      C
   I'm staring at the mess I made
(G)      D            Em      C(alternative Bm)
   I'm staring at the mess I made
        Em        D                  C
As you turn, you take your heart and walk away

C D C

        G  D
And it's you
        Em cadd9
And it's you
        G  D
And it's you
        Em cadd9
And it's you


          G       D
And it's falling down
        Em     C
As you walk away
         G      cadd9
And it's on me now
       Em C
As you go

           
(Repeat Chorus)

          G       D
And it's falling down
        Em     C
As you walk away
         G      cadd9
And it's on me now
       Em C
As you go

(Repeat Chorus)