With a well matched insulin to food regime you can be of normal weight.
If you have had high blood sugars for a while it is very likely that you have been peeing out sugar. This is an efficient way of getting rid of calories!
The high blood sugars are bad for your health long term and can make you feel very tired, irritable, forgetful and prone to infections short term. You are as well to get on and sort this problem out and if you need insulin several times a day, so be it.
What you can do is cut your calories a little, especially calories from refined carbs which are sugars and starches. The fewer of these in the diet, the less insulin you need to bring your blood sugars to normal.
It is also important not to overdo the insulin. Sometimes people who are on too much insulin get hungry or have low blood sugars and they then need to eat sugars and starches just so they don't end up having low blood sugars.