Read the following excerpt from Frederick Douglass’s “Learning to Read and Write” and answer the question.

As I writhed under it, I would at times feel that learning to read had been a curse rather than a blessing. It opened my eyes to the horrible pit, but to no ladder upon which to get out. In moments of agony, I envied my fellow slaves for their stupidity. I have often wished myself a beast. I preferred the condition of the meanest reptile to my own.
Which word is closest in meaning to the word writhed in the excerpt above?

visualized
squirmed
agonized
wiggled