Psychological resilience is the ability of the humans to recover very quickly from the difficult situation mentally and socially.
The traits shown by the resilient person are due to self-esteem, problem-solving skills, good health, self concept and many others which are considered individual-level protective factors as these factor help increase the well being of the individual.
Thus, individual-level protective factors are the correct answer.
I’m not sure if this is the right answer but the doctor would continue you to take it the few days after you have been feeling better to ensure the bacterial infection is completely gone?