Anyone else already receiving bills for a birth that hasn't happened yet?

So, today I came home from work to find a letter from the hospital informing us that we owe over $1,200 that is due before delivery (I'm 37 weeks exactly). At this point, I can go any time and I'm freaking out. Already, I've spent the majority of this pregnancy fighting with my health insurance because they have not covered a dime of any ultrasound, nor could they provide me with an alternative that would be covered even though everyone in the area is "in network". The hospital is also considered "in network" and I am just floored because maternity care is supposed to be covered at 100%. I'm just so frustrated because I should be worrying about things like labor and making sure that my little man is born safely and he's healthy, not about how I am going to pay for his birth.