As human beings, our need to socially connect with other people is innate. Loneliness can occur when there is a gap present between your desire for a social connection and the actual experiences of it. This gap can trigger a state of distress or discomfort. Even if you are surrounded by a lot of people throughout the day, you may still experience loneliness. Loneliness can threaten both your mental and physical health.
Anyone can experience loneliness, but the way each person experiences it is unique. It is completely possible to feel lonely without necessarily being alone. On the other hand, you may be alone and not feel lonely at all.