Give yourself breaks . When you feel overloaded, give yourself a brief moment to step away from your physical environment and breathe slowly while relaxing your mind. Don't focus on any one thought that pops up. Write down pertinent information. Better than assuming you'll remember.
Actors have a tendency to figure they'll remember . . . .
Studies have proven that writing down info locks it into even the most meager brains much faster and efficiently than using the gray matter alone. If you didn't get all the info right away, ASK the individual to please repeat or wait until afterwards and ask for the info again. Don't try to keep writing while the person has moved on. Get the info afterwards. The brain tends to lose focus when dwelling on missed info instead of focusing on the moment.