I used the easiest chords EVER. I hope it's correct :)


Verse 1:

 G                  D
   I know I've been holding it in
 Am          C
   The way I feel about u
 G                     D
   Something I've been dying to say
 Am                 C
   But I don't know how you'll take it
   Am               C
   Oh Please don't go
   Em          D
   You should know

  
PreChorus:

   G     D     Am
   These three words

   I've been holding back
   Am     C  D
   Trying to fight

   Imma let em out
   G     D     Am
   These three words

   gotta let you know
   Am   C D
   Here I go go go

Chorus:
               G     D Am
   Go screw yourse-e-e-e-elf
                  C
   I've had enough yeah
              D
   now we're done
              G      D Am
   Go screw yourse-e-e-e-elf
              C
   Not gonna lie yeah
           D
   It was fun

   But go screw yourself

Verse 2:

 G                    D
   Feels good just to get it all out
 Am            C
   it's so not overrated
 G             D
   U can't keep puttin me down
 Am               C
   And getting away with it
   Am       C
   Oh now I know
 Em           D
   The way to say

PreChorus:

   G     D     Am
   These three words

   I've been holding back
   Am     C  D
   Trying to fight

   Imma let em out
   G     D     Am
   These three words

   gotta let you know
   Am   C D
   Here I go go go

Chorus:
               G     D Am
   Go screw yourse-e-e-e-elf
                  C
   I've had enough yeah
              D
   now we're done
              G      D Am
   Go screw yourse-e-e-e-elf
              C
   Not gonna lie yeah
           D
   It was fun

   But go screw yourself

Bridge:

 Am                  C
   Guess I thought I knew you
            Em                D
   Now I know I couldn't have been more wrong
 Am                    C
   I had a feeling it would go this way
         Em            D                   G
   And I waited waited way too long to say
         D            Am
   to say these three words
         C            G
   To say these three words
         D            Am
   To say these three words
       C   C       C   C
   To say, to say, say-say

Chorus:
               G     D Am
   Go screw yourse-e-e-e-elf
                  C
   I've had enough yeah
              D
   now we're done
              G      D Am
   Go screw yourse-e-e-e-elf
              C
   Not gonna lie yeah
           D
   It was fun
            G      D Am
   Go screw yourse-e-e-e-elf
                  C
   I've had enough yeah
              D
   now we're done
              G      D Am
   Go screw yourse-e-e-e-elf
              C
   Not gonna lie yeah
           D
   It was fun

   But go screw yourself 


You can end with G :)
Hope you like it, xx