Ah, yes, I think we all are. If you know how much insulin to use as a correction dose then the fear should go. It's always a balancing act, but if you get to know your own personal needs then it's easier. Personally, and just as an example, I inject 1 unit of insulin for every 10g of carbohydrate. And 1 unit of insulin should reduce my blood sugars by 3 mmol/L which is the way my blood sugar monitor calculates it. I aim to be between 5.5 (so there's a leeway) and 7 and I know that I can rise to 9 after eating and it will fall when the insulin has had time to act.
If you keep a note of what you eat, what you inject and what your sugars do then you may begin to get a handle on your own needs.
I know that my own results can occasionally go awol, but I then act to get them in line again.
There are lots of things that can affect results: I believe for me the main ones are exercise - sugars used for making energy which lowers blood sugars, so extra carb - and illness, which raises blood sugars.
Can you make an appointment to see your DSN, or your GP, and see if they'll refer you to a diabetes consultant for more help? The Dafne course, or the local equivalent, would be ideal, but any further help from knowledgeable medics would be great.
I can really understand your fear at this stage. We're told that awful things can happen if we allow ourselves to go high, but the occasional high may not hurt in the long run.
I've had T1 for 48 years, have had a few highs and lows, and I can still walk, dance, see, feel with my toes, embarrass my children, travel . . .