I don't get angry that often now, but it has been almost 37 years. I used to cry but now fight back the tears. I think things through, deciding my options - increase this, decrease that, stop doing one thing, do more of another, what I should have said to this person, what I'll definitely say to the next one.
It does get easier - the longer you have diabetes the more in control you will feel. Six months isn't that long - I'd say it took me two years to stop resenting not being able to eat what I could before but with MDI and carb counting it's a lot better these days.
You are doing really well. In time you'll find you don't get so angry at the so many things that can disrupt our diabetic lives. If you do get angry . . . have you found our Scream thread? Sometimes just writing it down makes you feel a lot better!