how to recover from a panic attack?

This morning at around 5 I had a really bad dream and woke up crying. Usually when this happens I can fall back asleep pretty quickly but this time I felt overwhelmed and started sobbing. I was crying so loudly I woke up my mom who sat next to me and held my hand. I felt like I couldn’t breathe, started hyperventilating, and felt like throwing up. I eventually fell back asleep (the whole thing lasted about an hour) but since then I’ve been feeling like I have the flu, am really sad, and just completely emotionally and physically exhausted. My eyes basically teared up the entire day and I felt this overwhelming feeling of badness (don’t know how to describe it). I’m pretty sure it was a panic attack, what are you supposed to do to recover from one?

This is the first time it’s ever happened. 2 months ago, I got hit on the head and sustained a bad concussion. I’ve been out of school since then and have been feeling really anxious and sad. I’m seeing a therapist on Thursday. What else can I do?