Felling the alcohol only after everybody leaves

am i the only one the starts feeling the alcohol only after everybody leaves? if i go to a party or a barbeque with my friends i have no problem drinking until i get home or the party ends and everybody leaves, that’s when i start feeling dizzy and feel all the alcohol in my stomach. I also have a problem puking, i can’t puke when im awake, i only puke after i fall asleep and that’s quite dangerous