Make a blogpost talking about this, say you won't pursue users who pirate, but you hope that once they realize the value you provide they come to purchase the real thing.
Demonizing and chasing people who pirate will only work against you, just like it happens with gaming.
Consider the pirate version a "trial" for people who are considering whether to buy the official version. Again, many with gaming do this.
Don't feel bad. In all seriousness, piracy is probably helping you spread the word and get people to try your project.