I'm, mostly, the same way when it comes to writing. Come to think of it, I feel like all great writers are introverts at heart. Being transported and existing in that magical place of the creative flow, even for a little while, is very restorative.
I can tell I have the DNA of my father (extrovert) and my mother (extreme introvert) because I have both of these tendencies inside of me. I love to socialize with friends but then I need to retreat into solitude and silence to recharge the batteries.
RE: To fill these empty spaces...