I think it's his quick rise to fame that's getting to him. It's a song about him being homesick. He even said he wrote it on the flight Delta 1406 from Detroit to LA. He's a stranger around everyone and he's growing apart from his home. Maybe he also regrets leaving everything behind. His fame is a big subject here, especially when he says "Shooting stars leave no mark" meaning that rising to fame too fast means you'll just fall back soon, and have nothing to show for it.
I think it's his quick rise to fame that's getting to him. It's a song about him being homesick. He even said he wrote it on the flight Delta 1406 from Detroit to LA. He's a stranger around everyone and he's growing apart from his home. Maybe he also regrets leaving everything behind. His fame is a big subject here, especially when he says "Shooting stars leave no mark" meaning that rising to fame too fast means you'll just fall back soon, and have nothing to show for it.