If you're like me who spends any portion of the day in making and creating things, you definitely must have doubts about being original in your work.
I too struggle often with this. I don't think new ideas exists. They're just new combinations, perspectives, and versions of old ideas.
Here's the thing:
Why create anything if everything has been created already?
Watch this: David Lynch on Where do Ideas Come From
He says that ideas are like fish. You don't make the fish, you catch the fish.
Go see a doctor, if you'll not get at least an urge to create something today after seeing this short video.