Apologetics and evangelism takes patience. Engaging in people is a good thing and it is great too. I am sad too when people do not reply to me on Facebook. It is a lot of work and I can put in a lot of work and like get nothing out of it and that makes me sad.
Facebook? What is that? ;)
I spent a lot of time and effort developing work for facebook, linkedin twitter etc over the years. Very little engagement.
Post a picture of a kitten though and watch the flood.