Gestational Diabetes

So I was diagnosed when I was 29 weeks 3 days & in my recent appointment 2 days ago (currently 31 weeks 6 days) my doctor said that if I don’t get my sugars in check by next week which is my next visit then I have to do insulin . That honestly terrifies me because I’ve been dieting and walking but I still can’t manage my sugars and it’s so discouraging and frustrating . I really don’t want to do insulin but I guess I have no choice . Anyone else going through this or went through this that can help me because I feel like such a failure . This is my second pregnancy and my first wasn’t anywhere near as bad . I just keep stressing myself out and I just want my baby to be ok . Like what’s the side effects , what’s insulin like ? Please help !