Feeling triggered

Throughout my adolescence I never felt safe. I was diagnosed with lupus, my dad was drinking constantly and my grandma, who lived with me my whole life, was dying of cancer. This caused noticeable anxiety which made me a target for bullying. I thought I had moved on from those experiences in school but I haven't. I don't wanna go into the details but something really triggering happened the other day and I've been a nervous wreck for the past four days. I just feel so exposed and vulnerable. I really thought this was behind me. I'm having that same feeling or being trapped, unable to escape the threat. And I'm frustrated with myself for letting this have such a hold over me. After I dropped out of high school I publicly called out the school in a video review in which I played a recording of one of my classes to show the toxicity of the environment. It got like 2,000 views and the school's president emailed me saying he would do whatever he could to change the school for the better. Even after fighting back, even after I finished my freshman year of college with all As, one small moment can send me back to this place. I just don't know what to do anymore. This anxiety and insomnia are killing me.