I just told everyone that I had been sick and was on antibiotics!
We found out I was 7 weeks 2 days before we were due to fly out for BIL engagement party. No one suspected a thing, or those that did - pretty much believed my story! Then at work functions etc I just told everyone I was on a diet - so alcohol free!
Was pretty good at hiding my sickness. Altho I was sick at work I just told workmates the same thing, that I had a stomach bug - they forgot about it after a few weeks.