@Rosiehall You're on a mixed insulin so that will have a part that acts immediately and a part that acts later, eg an evening injection will cover your meal and also, with the other part, cover the nighttime to keep your BS in range.
So if you miss your injection because you can't eat your meal, you'd also be missing the part of it that covers the nighttime, if that makes sense.
I was on mixed insulin when first diagnosed and I was given alternatives to eat when I wasn't well so that I still got the right amount of carbs and could take my injection as normal. We're you given any guidance or information sheets like that?
With a stomach bug, things can be hard. If you have diarrhoea and/or vomiting, you're best phoning for medical,advice.
Test your blood sugar lots as illness can affect it.