starting to trip, losing my grip= ??

[NoClue]

Hello.
I'm trying to understand Avril Lavigne's song. I have always wanted to know what she means by Losing Grip. She wrote:
"I'm startin' to trip,
I'm losin' my grip and I'm in this thing alone".
This is from a song of the same name.

 

[Song Sprite]

Your grip is the hold you have on something.
When you 'lose your grip' it means that you cannot hold on any longer.

Metaphorically it means that you are 'losing control'.