If this is still continuing, I wouldn't suggest going to this particular group anymore. You Shouldn't be coming away feeling worse every session. You can have compassion for this other person without being a martyr for her. That isn't your responsibility. I am angry FOR you.
Your last post suggests that maybe you are feeling better about these sessions and if that is the case keep going. But if it's not and what you are really getting out of this is a reason to get out of the house and a sense of belonging, perhaps another support group, a MeetUp or other social group would work for you as an alternative.
You sound like an incredibly strong person. As such, I'm not surprised that you would become annoyed by people with relatively small problems who can't seem to deal or just want attention. Their experience did not prepare them for these issues, which seem miniscule as a flea bite in your experience. All I can say about that is to try to understand where they are coming from. Try to see your pain and experience as a privilege these people never had to suffer and this never had the advantage of learning from. What can roll off your back might be a catastrophe to another person. I think it was the podcast episode with Karma where she talks about how her trauma gave her this advantage that prepared her and her sister to survive under dire circumstances. Maybe that's why I'm thinking about this right now. Not at all trying to diminish your pain, but trying to encourage you to take pride in it (which it sounds like you have) and feel pity for those who don't have that. It's twisted, I know

Sorry this is long. It really enraged me to see how horribly your feelings and needs were addressed. You have every right to be angry!