My stepson moved to the U.S. from Eastern Europe when he was in 4th grade. When he went to school here he found out that the curriculum was 3 years behind, so in 5th, 6th and 7th grade he was still going over material he had covered already. Just FYI, U.S. public schools were created and designed to spew blue collar workers capable of self-discipline and mundane tasks. They were never meant to encourage creativity. Just enduring long dull robotic workdays.
School is here mainly to teach obedience, to domesticate children.
"The secret of American schooling is that it doesn't teach the way children learn -- nor is it supposed to. Schools were conceived to serve the economy and the social order rather than kids and families -- that is why it is compulsory. As a consequence, the school can not help anybody grow up, because its prime directive is to retard maturity. It does that by teaching that everything is difficult, that other people run our lives, that our neighbors are untrustworthy even dangerous. "
More here.
Feeling crazy in such an environment is normal reaction.