under weight!

Hi I'm type 1 the doctors worked out I had untreated diabetes long enough to build a high sugar tolerance, . No symptoms at bloods of 28+ and 4in ketones & was blissfully unaware ! But I've lost to much weight! I'm 5'7 and weigh 112lbs I should be between 130-160 and my bmi is 17.6 and should be 18.5! Any advice on how to build weight and be in controll of bloods?

But what are these? Like cheeses or meats?

I do eat cheese I make sure I get a cheese toastie for lunch most days 'ihave a strange addiction to mature scotish chedder' and I eat 50carbs in morning, around 30 at dinner & 40 in evening maybe some snacks inbetween, try nuts, and I was gaining weight at fir I gained 4lbs in a week lol but then lost it the week after! Then came the time of the month and bgl were uncontrollable even with more units of insulin then I was eating! And a chest infection days after that and still trying to regain full control at the minute it only seems to be last meal that's the struggle a little increase should help but I have hypos when in tight control, around 2-3 a day in bad cases so after treatment its hard to get back down maybe this is why I can't gain weight? :/ I shall try & see a doc about protein shakes maybe