Yeah, it's not an uncommon to feel this way, especially if you've not learned the humanities formally. Pretty much the first thing I learned in art theory at university was how much art depends on influence and appropriation, and that it's important to accept and embrace this. It was a hard lesson to learn as a young person striving to be original, but it's served me really well.

Even as I now move into programming, computer science, and industrial programming language research, I'm still grateful for that small amount of art theory I did at university. You don't need to try to be original - rather it's important to seek wide and varied influences, develop your sense of taste, and from that will flow seemingly unique and varied insights.