Struggling with Meltdowns and Overwhelm

Hi, I've been having a kind of nervous breakdown recently: screaming, crying, trembling, panic attacks, feeling nauseous, rage. I get sensory overwhelm from noise and sometimes see peoples movements speed up like static when I'm in a new or vusy environment. When I feel accused or unable to accept change and demands, I've been known to hit my head in frustration or have a meltdown. This has been something I did since I was a child. I'm scared I could give myself a TBI. I'm wondering if this is Autism/Asperges/ADD/BPD/PMDD/Bipolar. When my friends try to console me, I scream at them to get off me and can't handle physical contact or hugs. It's like something else takes over me, one minute I'm OK the next I'm completely crashing and out of control. Earlier this year I had a meltdown because the child nextdoor was screaming, I loose my focus and go into a rage and then if I don't let out the rage or self-harm I go into a panic attack and start rocking or clapping my hands. The only thing that helps is rocking, getting into the shower, and putting my fingers in my ears. It's been getting worse or more obvious the last 2 years since living by myself and since the pandemic. I had a huge meltdown at my GP surgery last week after a setback, I can't handle it anymore. I also can't deal with unexpected changes. Also, my autism refferal was sent back to my GP, saying they didn't receive enough evidence. Does anyone have any helpful suggestions? I can't keep living like this, hurting myself and scaring others. I feel like there's a monster living in me. I just want to be happy and live a normal existence. It's exhausting after every meltdown I need a few days to recover all my muscles hurt. I would really value people's insights. Thank you for reading. 🙏