Bday Vodka

So I’m in college, and this past Friday was my birthday. It also happened to be National Vodka Day, so we bought some vodka. I am such a heavyweight when it comes to alcohol (like it’s IMPOSSIBLE) for me to get drunk! Well, I drank 4 drinks (2 white Claws & 2 spiked Arnold Palmers)(1 pink Whitney & 2 Fireballs), and as usual, I did not feel anything. We then decided to open up the vodka (if it matters, the brand was Absolut), and we took 2 shots of it, but we should’ve just done 1. I only decided to drink it because it was national vodka day, but honestly I’m typically a tequila girl when it comes to straight shots.

I immediately felt off. The rest of the night went fine, but I still felt slightly tipsy. I didn’t really mind cause I wasn’t fully drunk. The next morning, however, I woke up and IMMEDIATELY threw up! I ended up throwing up for 6 hours, causing me to be extremely light-headed as I’d basically cleared every bit of liquid in my body. I am very certain it was the vodka because, as I said before, I never get drunk or throw up from alcohol; I also had had all the other beverages before, except Absolut vodka. The weird thing is I’m fine with vodka when I drink it in a mixed drink (and I love Smirnoff Ice drinks), but react awfully when I drink it straight. I also have had one (much smaller) shot of Tito’s before (a few weeks ago) and was fine, but we poured these shots into solo cups as we did not have shot glasses, so the measurements weren’t exact and probably more than it should’ve been.

Is there any explanation for this?! And if it was the vodka, than why did I not react to the Tito’s?