According to quantum physics theory, everything affects everything else. That means that as you are out and about in the world, you are being affected by the people you interact with - and even more so by the people you are within close proximity to - your family and friends.
Human beings are sensitive to one degree or another - the more sensitive you are, the more you are affected by others. If you are "Highly Sensitive" (HSP), or an empath - actually able to feel emotional states of others from one degree to another - your reality can be negatively impacted by those in your life who are difficult, abusive or unhealthy in any way. Some people are actually "energy vampires" who thrive off of the energy of other people.
For all of these reasons, if you are sensitive, being around negative or unhealthy people can drain your life force - your energy - and make you sick in the process.
To remedy this problem, you can withdraw into your own sanctuary. The popular opinion is that people who withdraw are "weird," loners, or socially awkward in some way - and there are people who fit that bill - but there are others who need to retreat to restore their own health and vitality and to "perfect" their own vibration.
A personal retreat might be living with pets in a beautiful environment (the right pet is healing - and provides unconditional love and companionship without draining your energy).
Eating a healthy, organic diet, drinking filtered water, listening to beautiful music, creating art of some kind (painting, writing, taking pictures, whatever inspires and relaxes you), taking Epsom Salts baths, using essential oils, sleeping in a comfy bed with beautiful bedding) - all of these things can help restore your health and help you "perfect your vibration."
Everything in the world is vibration - according to quantum physics, there is no such thing as matter - matter is simply slow moving energy.
Note how you are vibrating in the world, and when needed, retreat into your sanctuary to vibrate at your highest frequency.