By the time that we arrive at this point in scripture, Elijah has only been an active prophet for two chapters, but he’s already made quite an impression on the local royalty. After three years of drought, he pops up out of nowhere, blames the king, and proceeds to humiliate the prophets of Ba’al in the most ostentatious way possible (you can read about it yourself in chapter 18). He’s not kidding when he says he’s been zealous for the Lord - he’s made it absolutely impossible for anyone to ignore God’s power, including the queen.
But now, he’s feeling the full weight of his actions. Jezebel’s threats have left him feeling afraid, burnt out, and utterly alone, to the point that he’s ready to throw in the towel completely. God sends an angel to force Elijah to practice some self care, but the message that accompanies these provisions isn’t especially reassuring: “Eat something, because you have a difficult road ahead of you.” Great. Just what a person approaching wit’s end wants to hear.