walking proud PV and lyrics

[terra]

When I saw the pv without reviewing the lyrics i think it's kinda happyt pv, but when AT 05 comes, she cried when singing this 'happy-sad' song.

I wonder why??
But i have a theory....

'My lips told a lie
For a trivial reason
I suppose it was for no one else
But only to protect me
When I was thoughtless'

'When I noticed, I was trapped and at a loss
Surrounded by countless lies'

This means she remisce her childhood when she lied to herself that she could survive alone and make it all alone. She lied to make herself relieved and glad so that she could pretending living happily. But the lies she made never make her feel the real relieved feeling or glad either.

'The sky I looked up at was beautiful
I thought of you
I wished I could walk with firm steps
Facing forward like you'

This part gets me confused. Who is 'you'?? Is it her father which she longed for his warmth?? Whom could show her the path an taught her???

Maybe only that I could think right now....

Any other opinions?? Or could someone tell me the real reason she cried in this song???

THX