Drank almost a fifth of whiskey after being sober for 10 years

So I’m a female, 31 years old, 5’ 7” and about 160 lbs. I was addicted to heroin/pills when I was younger and had been clean and sober for about 10 years. I started smoking a little bit of pot this past year, then I had some family issues when I visited back home. I ended up at a hotel alone and drank almost an entire fifth of jack daniels in about 2 hours (maybe shorter I’m not sure). The next day I felt kind of shitty but nothing horrible. I was never a big drinker back when I used drugs, it was a rare occurrence. I’m wondering how is it possible that I drank that much? I’ve looked up BAL charts online and they all say I would be dead. Also why was I not really hungover? Any insight from people who drink more regularly would be greatly appreciated!