I liked this, I understood the beginning but the end was confusing me for some reason...

"Even if I was all smiles and cried at tripping at flat ground,
I was happy and there weren't times I felt so lonely:
now having everything I wanted's just not enough anymore,
there's nothing to fill in the gap I left open for a long time,
and it's all rotten and angry and so, so empty."

I didn't understand these lines above... What were you getting at?