Avoiding alcohol: how to hide TTC from friends

I live in WI (big drinking culture here!) and DH and I have a lot of single friends or friends without kids. Our social schedule is quite full, so I am always nervous about whether I should have a drink or not in front of others. On some occasions when I did not drink, people noticed and asked if I was pregnant! Sometimes I wish it were not such a big deal! I am always designated driver, so it's a good excuse. How do others handle hiding TTC around friends?