Sometimes I read stories like this and my jaw hits the floor, and I am not trying to mock you or be sarcastic. But you read what you wrote, right? You can't handle arguing but you have people living with you who are constantly arguing, which makes you afraid? And your therapist thinks you haven't made much progress? Could it possibly be due to your living situation-- it is akin to asking a battered woman to address the violence she's suffered while she's still living with her perpetrator.

I'm not sure you can address the real issues in your therapy until you're in a living situation that is safe. I suspect this isn't possible for you right now but I think that should be your first priority, above and beyond school. To put yourself first.

On the other hand, you can work on finding a way to feel safe in the midst of the arguing. You can explore what it means (a threat to you) and interrupt the pattern of physiological changes in your body that drive the neurological loop of coping. Because as an adult, their arguing doesn't pose a threat to you in the present; it's just evoking the past threat.

I do think this is a more productive route in therapy than focusing on your feelings, no matter what their content. Fear and what it does to your body are really, really hard. Once I stopped being afraid so much of the time I had all the space and time, it was like being able to take a deep breath. Fear messes with your head and the stress hormones that are released do a number on your body.