Rejection comes with the territory when you're an aspiring writer. You can't let yourself get dejected and stop writing altogether, but we're only human and so it can be a tough thing to deal with. We think about rejection, and the tiny crumbs of encouragement you need in order to keep going.
Stephen King, 'On Writing: A Memoir of the Craft': https://en.wikipedia.org/wiki/On_Writing:_A_Memoir_of_the_Craft