A hangover can feel like you're dying but a normal hangover will not kill you and is not fatal.
However if you do consume too much alcohol and get too drunk then you could die of alcohol poisoning but a simple hangover is nothing to worry about.
As long as you're overall healthy then the hangover should go away within 24 hours or less but it can feel like you are gonna die.
The last time I had a hangover was when I was 21 and just started drinking and I got drunk and when the hangover came I felt like I was gonna die and wished I was gonna die.
The hangover was terrible and it felt awful and made me never want to get drunk again.
I'm not suicidal and never was but just the feeling of the hangover made me wish I would die to get it over with.