Billed for top surgery

So I had top surgery 2 weeks ago. The surgery went well, and im recovering nicely. Up until this point, I had been told that the surgery was covered, but I received a bill in the mail for $460 for lab work from the surgery.

I was wondering if anyone else had this happen to them because this was never disclosed to me until I received a bill in the mail. This situation is frustrating because im a full time student and not working so theres literally no way I can afford this bill.