I thought that when I was first diagnosed - that it was medical science keeping me alive. But that thought did go away. I reminded myself that LOTS of people nowadays have been 'kept alive by medical science' eg people who've taken antibiotics, people who've had vaccinations, etc.
There's quite a long period of mental adjustment to having diabetes, I think. My only advice is to take one day at a time, concentrate on your health and to remember you're exactly the same person as you were before diagnosis and that diabetes, although a massive nuisance, doesn't define you.
Best wishes