"I was falling
and i fell too deep"

Capitalize your "i" and add some punctuation, I really think you could expand on these first two lines, there needs to be more detail and emotion.

"Now i can't get out
the walls too steep"

Capitalize your "i", and add "are" after "walls" for a better read.

"And i scream
and i shout"

Capitalize your "i"s and there needs to be more wording here, its a little bland.

"Waiting for someone
to get me out."

I felt the ending to be weak, add more imagery and creativity. Take care and keep writing....

I hope you understand I was twelve-years-old when I wrote this and was not necessarily looking for criticism.