I echo what others have said: it doesn't matter if this is your 1st or 100th "Day 1," you only have to worry about today. You can't change yesterday, and tomorrow doesn't exist. Waiting for the other shoe to drop is fatalistic and a self-fulfilling prophecy. You expect to fail, so you give up and allow yourself to fail.
When I was newly sober, I remember thinking even 24 hours was too difficult to get through. I was at the point where I was just staying sober an hour at a time. But I did it, and so can you! It is very simple: don't drink, no matter what. Simple doesn't mean easy, but there really is no trick to it. Making a list of alternatives or plans to help yourself keep from drinking are helpful, and also lists of people you can call. And I would also suggest focusing on sobriety. This isn't the time to overhaul your entire life, as tempting as it may be. Wait on major life decisions, avoid starting new self improvement plans, and changing relationships. When you are struggling to stay sober, your perspective of yourself and the people and situations around you isn't always accurate. You have one task today: don't drink. You can definitely do this!