Being ill and under the 'weather' for what ever reason combined with diabetes is often a problem, especially when it comes to controlling B/G levels. I'm sorry but there is no easy solution, it's a case of frequently checking your B/G levels and adjusting insulin dosage if necessciary against what you are eating to try and stabilise the levels.
Being on insulin can in these instances make control more difficult to acheive, and if you don't feel too well which would be likely and not eating as nornal, then it might be advisable to reduce the insulin dosage. It's normal when you fell ill to cut back or avoid food, but you should always try to eat as food is the principle source of energy which your body will use to fight against the illness.
When you are ill the body will frequently loose it's normal control of B/G levels hence your sudden rise in the B/G level. I would suspect that it would NOT be a good thing under these circumstances to increase insulin levels in order to compensate as this might result in wide B/G swings from High to dangerously low levels.
I'm fortunately not on insulin myself, but hopefully someone who has had personal experience of your current difficulties can shed further light.