Help!!

My husband and I just found out we are pregnant!  ☺️  About 5 wks along, so we are not ready to tell anyone yet. My sister is getting married in 1 wk, and I am the MOH. My family will definitely know something is going on if I am not drinking. I don't want to announce anything as it is early and don't want her day to be overshadowed by it either. Any tips on how to hide not drinking? Advice is much appreciated!