Do i have insulin resistance?

during the last year i have been putting on a stone every 2 months,i have put on a total of 6 stones,and am still gaining at the same rate,have had thyroid checks(| have been on thyroxine for years)all tests have come back ok,also had tests for cushins,and allergies as i am also getting severe hives every day and now have to take piritol every day.i am 42 yr old female,with family history of diabetes and heart probs,i am not diabetic,but wonder if i have pre diabetes,insulin resistance,and my diet hasnt changed,although i have cut out most refined foods and sugars recently.can anyone help,thank you,donna