Congrats on 6 months and on the new job. I used to travel a lot for work and still do to a lesser extent. I just keep it simple. It is often as easy as ordering a soda. Most people will not care nor will they give it a second thought. After all, lots of people choose to not drink alcohol for many different reasons. If they ask, I prefer to be honest but that doesn't mean I have to give details or a confessional. I try to limit my soda intake so I explain that to them and let them know that I reserve it for a special occasion. That is true and in a very real sense, I am celebrating and enjoying myself and my diet coke right along with whatever they choose to drink.
IMO, not drinking is a safer approach for any new employee anyway. I think it is very rare that coworkers get suspicious of someone that simply chooses to drink a diet coke. However, I am pretty sure that drinking alcoholic beverages, especially several of them can start to raise eyebrows of at least some individuals.
Stay safe, sober, and healthy. You can do this.