I've experienced quite a similar situation with a friend, and as you stated, what they're doing is likely either out of ignorance and/or neglect of your situation. No matter which of the two it is, (based on my results) it's best to stand up for yourself, set hard boundaries, not let their opinion of your situation (which they are not the one undergoing) affect you in any way, and if necessary, cut them out of your life. You aren't being a "little bitch" for having a panic attack, and you don't need to "get over" your trauma. Of course it would be ideal to magically "get over it," but that can't happen with the snap of one's fingers, and it's wrong of someone to demand such a thing of you. If you can't help it, you simply can't help it and no one has the right to claim that you actually can. You're the only person who knows your current emotional/mental state, and they most likely aren't a mental health professional haha.