Why no hangover?

Maybe this isn’t the right subreddit for this question, I am not a connoisseur of alcohol related subreddits. Anyways I drank for the first time yesterday at my buddy’s house after his grad party. I really just wanted to see how much I could drink. (I know stupid) I ended up drinking a gallon of beer, give or take a few ounces, in 90 minutes. Which for me it said my BAC would be an estimated .21.

I ended up puking and just sitting on the ground in pain for a couple hours before I felt like I could head to bed without puking on the mattress. I woke up feeling fine, the only thing that bothers me is my stomach. But that always happens the day after I throw up.

Do I just need to drink more and get a higher BAC to get a hangover. Or would I need to put back a few shots. Idk