Your daughter's body was struggling to process energy before diagnosis. Now that she has more insulin it is happily processing energy. She may be building back energy stores that were depleted. Being hungery is normal.
Many others have spoken to the feeling of being overwhelmed. Real normal.
You are on the right path. The good news is you have a medical team and now that you are here and emotional sounding board. Use both. It is very easy to read ten thousand things on line and being a good parent, you may feel compelled to explore them all. Diabetes is different - in every child, adult, and in between. Maybe those in betweens the most. It is different day to day in teh same person. My 2¢ is to learn early that Your Diabetes May Vary. YDMV.
Read and absorb and take small steps Just last week I was talking with a woman who has lived for 53 years with type 1. Long and productive lives are not only the goal, they are the reality.
All my best.
BD Dad of 4, 2 are T1.