Hi, No it's not just you! Looking after a diabetic child can be a challenge at times, but as so many of the other posts have mentioned, by learning to carb count it does make the management easier and will hoepfully give you less volatile readings.
I have 3 children, 2 of which have type 1. I have to keep a food diary for both of them and this enables me to work out insulin doses. Carb counting is not an exact science and I often get readings that are unexplainable, but by knowing what insulin to give depending on what consumed is a big advantage in managing this condition and will give you better control which in turn will mean you won't be worring so much about his readings.
Soon after my kids were diagnosed I was getting fed up of people not really understanding their condition and it would upset me when people asked me lots of questions (even though they meant well). In the end I drafted a document which basically outlines their condition, treatment and info about hypo's. Now i simply hand this out to any parent who is interested and to those who are having my kids to play.
I think it's great that your son is doing his own injections. It always amazes me what our kids can do and it just goes to prove what little STARS they really are. Good luck