Do you ever feel like a plastic bag
Drifting throught the wind
A plastic bag in the wind will look round. Therefore, the noun "plastic bag" here defines as a fat person. The wind is a thin object and its also an uncountable noun, so it symbolises many. So the meaning of this part of this stanza is:
"Have you ever feel odd being a the only fat person among many thin people"
Because of the second person is sensitive, it might be a 'she'. So the more probable meaning is:
"Have you ever feel odd being a the only fat girl among many thin girls"
sori la x siap lagi. ngantuk sgt. nak tido. gnight