Im glad you’re happy doing this, really. To some extent, I also post my favourite shots for free on FB and Instagram — I’m not familiar with Unsplash. Certainly being passionate about what you do should help you produce better results than if it were drudgery. The professional photographers I know — and I’m one of them — are passionate about their work as well, and they’re well paid for that passion and its results. Companies advertise for, hire and pay people who are passionate about the jobs they apply for. If companies are using and profiting for your work, though, I strongly believe you should be paid for that.