"Upsetting experiences"

I struggle to access GP care due to previous traumatic experiences. I keep finding that staff are rude and speak harshly both over the phone and in person. When this happens I instantly panic and have to tell the person to stop as I need to leave. They then get worse and on three occassions have started actually shouting at me. I've never raised my voice or been rude and they know on my file I have panic attacks easily when attending medical care so I don't understand why they don't try and help me and instead just act like I'm being difficult. My PTSD is a disability and instead of being helped to access care I'm being almost blocked.