I know everything you’re going through, and the unpleasant answer is that, for me and i assume many at least, stuttering never completely goes away. I was fortunate i guess and had speech therapy, but i still stutter to this day and its more or less manageable. Much of the insecurity you describe i feel is still much a part of me as well, and between the stutter and the the way it made me feel all those years, i can only say that the way i felt struggling with it was worse than the actual disability. It is hard, but you are not powerless. With enough practice you can get it under a control. The hardest part though is not letting it make you feel like you are less than other people. Im sorry that you seem to be surrounded by such insensitive people, but you are never alone. For me, i heard some similar nonsense like people didn’t think it was really that dehabilitating. But please be strong. It does get better.