Most people are polite enough not to comment when they see you looking a bit bigger, so I wouldn't worry about 'having' to tell people sooner. And if it is bloatedness, not actual baby, I was advised by my FS to eat lots of protein when I got very bloated after embryo transfer. I added a glass of sustagen to my diet, reduced my carbs for a bit and made all my snacks protein-based - peanut butter, nuts, cheese, etc.