No, it's not a disease at all. What you described is actually a relatively common phenomenon, and it's a normal part of human behavior and personality. Many people exhibit different social behaviors depending on the context and the people they are interacting with.
What you are experiencing is often referred to as being an "ambivert." An ambivert is someone who displays both introverted and extroverted traits, depending on the situation. Ambiverts can enjoy social interactions and be outgoing when they are around close friends or in familiar settings, but they may also need time alone to recharge their energy, like introverts.
Being an ambivert is considered a healthy and adaptive personality trait. It allows you to adapt to various social situations, maintain meaningful connections with others, and still honor your need for solitary or quiet time when necessary.
Remember, personality traits, including introversion and extroversion, exist on a spectrum. Very few people are purely introverted or extroverted; most individuals fall somewhere in between. Embracing and understanding your unique personality can help you navigate social interactions and ensure you take care of your well-being.
So, rest assured, what you experience is entirely normal and not a disease. It's just a part of the diverse and beautiful tapestry of human personalities. Embrace and celebrate your ambivert nature!