Some great answers here, I'm going to offer up something different, and suggest you start understanding WHY you feel the way you do. Essentially a psychological journey if you will :)
Do you know what Imposter Syndrome is? Briefly explained, it's when you think you haven't "earned" your way up to whatever point you are in your career. Most, if not all, developers have gone through it at some point, usually doing the exact thing you are doing, trying to learn a new technology. You feel a bit hopeless, doubting your ability to learn it, and it can be quite depressing.
But there's good news! You'll pull through it, and learn it. How do I know? Well, you've done it before, haven't you? I assume you're not a magical Imp from the 4th dimension, and that you actually had to learn all of the skills necessary for your job now, right? Oh but those skills were easy you say? Could your grandmother do your job? After all, she's been around a lot longer than you, and has much more experience, sooooo....of course not :)
My point is, if you're a developer of any sorts, or even someone with a particular craft/trade, then you're ability to grow is only limited by your desire to put in the effort. What we do is NOT easy, and there's a reason why there's a shortage of programmers here in the States.
So go study, put in your time, try to have some fun, and in time, it'll come to you :)