The average salary for developers is roughly in 80-100k. As a recent grad, almost all of my peers were in the 60-125k range. The only salary I've seen that was grossly under the average was 48k- but that was expected.. the employer was TXDOT.
Edit: Please assess your contributions and value yourself at market value. Having a conversation with your manager about your market value should yield a higher salary that is competitive. If not, move along. As a mobile developer, you could be contracting for much more than 45k.
He said I'm "lucky to make this much" because I have no education, despite nobody else on the team being able to successfully and efficiently replace me. I'm leaving in one month, only because the project is wrapping up at that time and it would be pointless to quit earlier. I can't wait.
Surprised you would only make that little - I started as a frontend developer at a non-profit for $51k, which is also under the market (and a non-profit to boot).
Depending on where you live, you could easily fetch $20k more, if not even more than that.