Hugs, Carla.
Life will be normal again, but a different kind of normal. Have you had any kind of education about how to manage your daughter's diabetes? It sounds as if you must have had something to be getting such good BG readings, or have you done it by instinct?
If the nurses won't (or can't) answer their phones then why not pop down to your GP and say so and ask what the next step should be. There should be a diabetes nurse in your GP practice. She/he probably won't know a great deal about managing the minutiae of it, but will have a great deal more experience than you have right now and should be able to help you straighten out the knots and terrors in your brain.
There are some very good resources that others can point you at on the internet, which will help you work out how to balance carbs and insulin until you can get some solid input from the flesh and blood people in your support team: when you have one. I can't tell you where the education things are on here, but others know.
Diabetes is not the end of the world. It is complex and takes a long time to learn the ins and outs of, but there is lots of help and support in here if you can't find it out there. Don't be afraid to ask as many questions as you like and don't be afraid to ask the ones you think are 'silly questions'. If you don't know the answer then it is not a silly question, it's an answer you need to find out.
Once you have got over the shock a bit and got your head round how it works, life will get to be normal again. As I said, it won't be the same normal, but it will become normal to you, as it has to every one of us in here. And when 'normal' takes a holiday and you have to deal with hypos and hormones then come on in here and we can hold your hand and talk you through it.
Please trust me on this next one: your daughter is not half as scared as you are right now. I know I'm not inside her head, but things like this are always worse for the people watching from the outside than they are for the people they are happening to. I was older when I was diagnosed at 17, but my Mum was infinitely more worried than I ever was. I was annoyed, shocked (but didn't realise that until much later), inconvenienced, lost the chance to follow a couple of careers that had been on my 'would like to try' list and many other things, but I was not scared. It is now 36 years later and I have no complications and still lead an active life full of things to do. Your daughter can too, with your help and education. Incidentally, most of those things on my careers list that I couldn't do then are no longer banned. I'm training to be a driving instructor now, and I wasn't allowed all those years ago.
One last thing, and I expect you will do this without me saying but I'm going to say it anyway. Try to involve your daughter in every little thing you both do to control her diabetes, so she learns to do it herself and does not lose her independence and become reliant on you. She should be taught by her healthcare team, and so should you, but it doesn't always come together perfectly, so you need to share every decision and explain why you think she should have just that much insulin, or eat that particular food, or change how much insulin she has because she fancies going for a run... etc. And then listen to her reasoning too. Not of course, to her denials and wrong stuff, of course, but... Oh heck! I''m getting bogged down here. I hope you get my point: be careful not to let yourself think of her as a three year old again. It is so easy to do when there is such a huge thing to take care of and it's very, very hard to let her make her own decisions and be a grown up.
There are people who go into schools to teach the staff if they have a diabetic pupil to care for. I don't know who organises it, but I'm sure someone in these pages does and can point you in the right direction.
Good luck, keep strong and don't let it scare you too much. It's cool. 8) 8)