I like the definition of extrovert and introvert that says that extroverts are regain their energy by being in group whereas introverts regains there by being alone. According to that, I'm an introvert, I need my alone time so that I can recenter myself and recover my energy. I do feel drained when being in events with a lot of people.

But, that doesn't stop the fact that I do like people, I like organizing parties (or rather I don't particularly like the organizing but I like the result of having organized parties and having close friends) at my place and regularly invite friends. It's just that after that I'm exhausted and I need some alone time to recover. So being an introvert doesn't imply that you shouldn't make effort to reach out to people or that you won't enjoy being with others. It just means that having some alone time is necessary to recover.