So. To my understanding and from my million times listening to this song: the song is about two people getting really drunk and having sex with each other, a one night stand essentially, and he wakes up in the morning hungover with a headache and he likes the girl he had sex with but he probably can't have her for some reason probably because she just wanted a one night thing, that's why he's fucked. He gets feelings and grows attached and even though a lot of feelings of guilt and regret come from one night stand, he doesn't feel any of that (even though he knows he should) because he actually likes her. YOURE WELCOME
So. To my understanding and from my million times listening to this song: the song is about two people getting really drunk and having sex with each other, a one night stand essentially, and he wakes up in the morning hungover with a headache and he likes the girl he had sex with but he probably can't have her for some reason probably because she just wanted a one night thing, that's why he's fucked. He gets feelings and grows attached and even though a lot of feelings of guilt and regret come from one night stand, he doesn't feel any of that (even though he knows he should) because he actually likes her. YOURE WELCOME