There is a lot related to writing that is not writing. And building your base of followers is at the top of the list. If you do not have followers, who will read what you write? Let me ask you something. How do you make friends? Do you go to any Bible studies? To church? Any craft groups or other groups? Have you made friends?
This is exactly what the groups like FB and Twitter are on social media: outlets for connecting, for making friends, relationships. That's where you talk about your family or not. Share recipes if you like. Ask questions to get others involved. Yesterday n FB, I asked what everyone's favorite Christmas cookie was. When you have a blog post, you post that. You share things you've seen.
I'm an introvert but I've learned how to come out of my shell, albeit somewhat. So, don't give up, RL. And besides, no one ever said you had to join multiple social media sites. If one is your limit, then that's what works for you. Keep at it. You can do it!
PS Let me clarify. By groups, I meant like FB. However, there are tons of groups on FB that are well worth joining. There are Christian writing groups, prayer groups, women's groups, etc. Great places to get connected.