Need advice about a medical bill.

I had a surgery in January, that my old insurance company referred me to get. All the while I was told that they would cover all the costs except my co-pay which was $250. I just received a bill yesterday from the hospital I had the surgery at for nearly $150,000 and it indicates that my insurance paid nothing at all.

About two months ago I moved out of the state I was in, and had to switch insurance companies.

I'm beginning to panic because up until now I had thought it was completely taken care of since my surgery was nearly 7 months ago and I never received so much as a phone call to tell me something was wrong.

Since it is the weekend I cannot call either the hospital or my insurance company because both of them only operate during the week.

I plan on calling them on Monday morning but. I don't know what my options are? Do I have to pay the $150,000 for a surgery that I had been promised by my insurance company that they would cover and that they referred me to the surgeon for?

Appologies for typos and grammar, I posted this from my phone. Any advice is helpful.

UPDATE:I called the insurance Company and the hospital. Both say that they have negotiations pending. So both say I don't really need to worry about the bill since a claim has been filed with the insurance company. So im gonna call them before the bill is due just to make sure. Thank you all for the advice