Credit score/debt collection

I had to make a trip to the emergency room last year and I never received a bill for it only letters from my insurance showing what was being covered. I just checked my credit score and it dropped and said that the medical bill went to collections. I'm angry and confused because I feel like the hospital should've sent a second notice or something making sure I got the bill. Now that it's in collections I have no idea how to make payments on it or who to even reach out to