Unwanted Pregnancy: How to act pre-abortion?

I just read this article at Sociological Images. It got me thinking about something that happened lately with my mother and I.
My mother (who is pro-choice and sex-positive, but a little uptight about women and drinking) and I were on vacation with some other members of my family – there were 9 of us there in total. My family tends to party pretty hard; when we go on vacation together, now that all of the kids are of legal age and none of us have our own kids yet, we’re at a really fun time in our lives. We go out to bars together when we’re on vacation and share pitchers of beer, bottles of wine, and many laughs. It’s mostly my dad, my uncle, and all their children, because my mom and aunt aren’t as big into it, but they usually get in on the fun for awhile. My family is really close and in many ways I can party with them and have as much crazy fun as I do with my friends in their 20’s. I love it.
So anyway, this recent vacation was pretty short and because of that, we crammed a lot of fun into a few short days. We all drank quite a bit. And on the way home, at the airport, I unexpectedly got my period. I have never been more relieved to get it; it was almost 3 weeks late (unusual for me) and I was understandably pretty worried I might be pregnant, even though a home pregnancy test had already informed me that I wasn’t a week earlier. The period was just a welcome confirmation that the negative test was correct.
I had to get my mom to help me track my cousin down to get a tampon from her, and because I was just so relieved, and I wanted to tell someone (anyone) how relieved I was and my boyfriend wasn’t around, I told my mom that this was great news when she made an arbitrary comment about how it sucks to fly with your period.
She was really concerned that I had been willing to drink so much while I could possibly have been pregnant, and I was a little surprised to hear myself respond with, “Well, it’s not like I would’ve kept it anyway.” My mom, who I know would completely support my decision to end a pregnancy, gasped in horror at this statement.
A part of me gets it. I said it very casually, and even surprised myself with the easy tone at which I made such an admission. But the thing is, it’s true; I wouldn’t. My boyfriend and I have talked about it: We’re not ready, and if I get pregnant at this point in my life, I would get an abortion. We’ll of course do everything in our power to avoid a pregnancy (short of abstinence) but if it happens, the pregnancy will end, and he’s fine with that, and so am I. My mom believes in that right; we’ve talked about it before, she knows that’s what I’d do, and she trusts me to make my own reproductive choices.

So then, was I wrong to drink while knowing a pregnancy was a possibility? (This wasn’t just a glass of wine or two, remember; I had been getting pretty drunk all weekend.) But I had taken a test, which of course isn’t a 100% certainty but it meant pregnancy was pretty unlikely; and, if that unlikelihood had been a reality, I know full well that I would get an abortion as soon as I found out. If I were unsure and I had some reservations about whether abortion was the right choice for me, I could understand holding back on the partying, but that simply isn’t the case. On top of this, I’m usually a big partier, as is the rest of my family; if I were to avoid drinking the whole weekend, it would have been pretty clear to everyone there that something was up. So why hold back from drinking when there is a very slim possibility that I could be pregnant with a fetus that I would eventually abort anyway and I wouldn’t necessarily want my whole family to know about it?
This is just a prime example, to me, of how deeply ingrained it is for everyone in our culture to be the Pregnancy Police. Pregnant women don’t drink heavily, it’s simply such a nightmare to imagine. Furthermore, my mom has always been a little Victorian in her attitudes about women, propriety and drinking for some reason; she lets loose quite a bit herself sometimes, usually when she’s at home with a few close friends and family, but she’s always hard on herself about it the next day and it bothers her that I have more my dad’s attitude toward alcohol – I’m pretty carefree about drinking. My dad is almost my drinking buddy; we have a certain sports-bar-and-beer bond that maybe my mom is jealous of, or simply thinks is inappropriate. (My brother is more like her, and maybe she thinks this type of bonding should be reserved for father and son, although my dad and brother have a good but different relationship entirely.) She has disapprovingly called me a “wild woman” in the past, even though my drinking habits hardly constitute wildness or even unusual behaviour among women currently in their 20’s.
But what this is really all about, even more than all that, is that an abortion shouldn’t be such a simple decision. It’s supposed to be an excruciating internal battle, a devastating choice for any woman – and that’s simply not the case with me. I haven’t had an abortion, and therefore can’t say how I’d react to the situation post-abortion, but I know I would make the decision firmly, and I should get credit for knowing what I want to do with my own body.
So tell me this, commenters: If you were possibly (but not very likely) pregnant and knew full-out that you would get an abortion if you were, what would your attitude toward drinking be?