Tolerance to alcohol while pregnant

Now I KNOW you should not drink while you're pregnant! So let's just get that out of the way. But does a woman's tolerance for it go down while pregnant? I've always always had a very high tolerance for alcohol. No matter what it was, I would just drink it like water. It took a LOT for me to get drunk. But the other night, day 48 of my cycle and after probably 30 negative tests, I decided to just have a margarita. It had been a long hard week because we were moving and working and all that fun stuff. So I had one cup and I was tipsy. And I was like,okay... Weird. So I got another one and halfway through that one I was done. I was slurring and tripping and I told my SO "watch. I'm gonna get my period tomorrow. No sense taking anymore tests!" and I was right. Period started next day. Ended 2 days later.