@NoKindOfSusie you're right, it isn't your fault. You are stressed about your diabetes, who wouldn't be?
It will take time to get used to the Type 1 way of life, and acceptance of it, warts and all.
Perhaps you've had an unfortunate experience at the clinic. Maybe someone has, in one way or another, said that it's your fault your BGs are out with your target. I know that 5 weeks to the day after diagnosis, a junior doctor walked into the room, looking at my notes, and said, "You've been cheating in your diet." I was stunned and couldn't believe anyone could say that to me.
That, along with a couple of other episodes at clinic, has given me a great distrust of doctors at the clinic. I really hope you haven't gone through bad situations like that.
As others have said, you can aim for a target of 5 - 7 but it is only a target. You could be lower or even hypo, due to exercise, or even for no particular reason. You could be higher because you're coming down with something, you've had a different type of exercise, you've eaten something different (or more than intended) or for no apparent reason.
Try and relax and be kind to yourself. No one can expect perfect BGs all the time.
There is a lot of trial and error in our diabetic lives, until we find what works for us. That will work for a while but then it won't and the trial and error starts again
You will get used to it, e.g. you will get used to planning for exercise (lowering bolus and/or basal insulin) BUT IT WILL TAKE TIME.
Give yourself a break and don't expect perfection. Yes you might get complications, but you might not. I'll have my 40th diabetes birthday later this year and am still going strong. You can only do your best, trying to follow advice. Sometimes it will work, sometimes it won't.
It took me two years to accept my situation. There was a lot of anger, distrust and crying into my pillow at night, but I got there in the end. You will too!