Sergey Lazarev - Heartbeat

Hi!
My English isn't perfect, so I need to ask somebody for help. I have a song. It's not a great song, but I need to write down the words. I think, it would be easy for a native speaker or any person, who speaks English fluently. But not for me. So, anybody! help me! Please!
The song is here http://www.youtube.com/watch?v=vt1Exv99cK0. I know almost whole lyrics, but I can't make out two lines in the second part of the song. Second part starts at 1:40 with these words:
I know that I'm not supposed to be feeling the way that I'm feeling inside
I carry on with may day but nothing goes my way trying to understand why
... What does he sing afterwards?
Please, help me to make out next two lines.

I know that I'm not supposed to be feeling the way that I'm feeling inside,
I carry on with my day but nothing goes my way trying to understand why,
This thumping in my brain is driving me insane, why did I let you go,
This rhythms never ending my heart it isn't mending, because I need to know.