Oh Emma, I just want to give you a big Mummy hug! I am the complete opposite to your parents, my son is a T1 and thinks I know TOO much and wants me to back off! I can't help it, I feel a desire to know as much as I can to help him and make sure he lives a long and healthy life.
The one thing that struck me about your post was the fact you had a BG reading of 18 and you 'rode the storm'. Didn't you have a correction dose of insulin? I am assuming you are on MDI with some rapid acting insulin? That would have brought you down pretty quickly and made you feel significantly better I would have thought.
My son's HbA1c started at a shocking 15.8 but within weeks it was in the 7's and after a few months we had got it right down to 6.1. We did that by being pretty fanatical about carb counting. It really wasn't that difficult though. With a pair of modern digital kitchen scales I weighed all his carbs at mealtimes (rice, pasta, potatoes etc) and allowed for a yoghurt or whatever dessert was going to be and calculated his insulin needs from that. I typed up a list and laminated it of all the common things we eat and their carb values - started with cooked rice & pasta, potatoes, bread, then got onto fruit, then things like baked beans and kidney beans, and odd processed things like chicken kievs and fish fingers, I even calculated how many carbs in a batch of homemade yorkshire puddings and fairy cakes and we now have a pretty comprehensive list which I can quickly refer to. All packaged food has the carb information on it, so between us we always knew how much insulin he needed for his breakfast, lunch and dinner. It really doesn't take long to get into, it becomes second nature and you soon know many of the values without looking.
If you remember to test just before eating, you will have some idea if you are still too high and need to add a unit or two of insulin to correct a bit, and before you know it, levels become much better.
That's not to say we have the magic answer, my son then rebelled and stopped injecting at school, then 'forgot' to inject for his main meal at night, and his HbA1c at Christmas had risen shockingly up to 12. He was also not bothering to test either for weeks at a time. His regime has now been changed so he doesn't have to inject at school (he has a mixed insulin at breakfast time to see him through the school day) and it is slowly coming down again.
As others have said on here in the past, testing is the real key, it does show you where you are at, whether your basal need tweaking, and tells you immediately with each meal if you need to correct. Maybe just getting in good habits of testing 4-5 times a day would be a good starting point?
I think it's very positive that you have realised it is becoming a problem, and you want to do something about it. Keep coming on here (when you have the time!!) as everyone is so friendly and helpful and they 'get it'.
Good luck with it all, and the very best of luck in getting a new job. What a pain with what happened over your new post, especially as it's something you wanted so badly. Something will turn up though, keep smiling
Tina xx