Chord changing .

So I'm practicing "Consuming Fire" on my guitar right now .

And so far no progress . . .


The D/F# and G/B gets pretty hard to change to for me from any chord .

And I don't really understand the strumming pattern , cause it seems when I play the strumming pattern Zhe Xian told me to play , it's as if I played that chord for too long when I'm looking at the song sheet as when I'm trying to finish the whole pattern for the Em chord , the lyrics says that I should already be playing D...


Hmmm.


I don't think I'm playing fast enough ? Or am I doing something really wrong that I didn't notice?