It's easy to equate fluency with success. You're putting yourself out there in groups and that is most important. The more you do it, it will get easier and more fluency will be a byproduct. It's easy to get into that "downward spiral" moment of stuttering. There are a few things you can try. Maybe for starters, when you start feeling like this, pause and just remind yourself, I am stuttering and it will be ok.