Massive economy..drop (White Giant)

Well for the last 1-2months
5-7weeks ago= I've been watching my country go into debt little by little. I thought it was a small problem at first but then something happened. I had 4trillion and my economy had its little ups and downs. It was losing 50billion then it would gain 50billion so this little economy fall wasnt a big deal.
Then boom..
4 Weeks ago = I was tanking 100-200billion even 250-300 on some days really bad days, so I raised taxes to 30%(original 20-25%)around a month ago but then money was still slipping. I bought more pop to make more corps. But it didnt help, Then I have no idea what happened but in the last 2-3weeks my corperations values dropped from a average of 1.2-1.5trillion value to 50-300 billion and then my money turned into flames
I'm in a debt of 780billion.
I payed 200billion off and my corps are now around 300-500billion but some are still in the 30-100billion range.

So I need some major help...is this what real stock market crash is like

Country name = Corleone Family

Half of the corporations in Corleone Family make roads, which are in serious oversupply on WG. You should probably shut the weaker ones down and diversify.

Also, the tax rate only affects the 5 privately held corporations. You may want to consider lowering the tax rate to zero and inviting in more private corps. They generate more income for your country than state-owned corps do, even at zero tax. Having CEOs as employers also allows you to expand your workforce through special clinics and back to work schools.

roads are unreliable
get rid of an go for power, service, household or air tran

I have found that road making is a very unreliable business. Electric power is the corporation to go for. Also, Chemicals, Services and Construction are good as oversupply does not last long for these corps.

let the c3s make the roads, schools, and such
hospital is the only reliable gov company