Struggling in Silence

I'd say right now I'm struggling in silence. I have severe anxiety due to PTSD, and when it flares up I completely shut down. Can't talk, can barely leave my bed, can barely function at all. I've tried to talk to people about it but it seems as though nobody truly understands the extent of it. My girlfriend gets upset that I won't talk to her, but I physically can't bring myself to engage in conversation. My mom is constantly trying to talk to me and I feel terrible because I can only respond with nods or hand gestures a lot of the time. It's a complete 180 from my usual personality, I'm a very expressive, talkative, and bubbly kind of person. Always cracking a joke, always laughing with people, always complimenting people. During my original flare of anxiety that was the start of all of this, even the ER doctors didn't (or maybe didn't want to) know what to do. It just feels like I'm stuck being scared of everything every minute of the day and it's very suffocating. It's very lonely, and thankfully it seems that days are slowly getting better throughout this bout of anxiety, but I really wish I had somebody that truly related to the way I feel.