What does bubble dreams mean in lady gagas song speechless?

The lyrics to the song "Speechless" are about Lady Gaga being unable to speak as well as she desires to, feeling vulnerable, but she remains defiant in the face of it. Some have suggested the bubbles mentioned represent that vulnerability. But, it's most likely it simply means she had been drowning under the pressure. She sings the lines "Finally drowning. Bubbles, bubbles out my nose". In this scene of the music video she breaks free and takes off walking from everything.