Tips on how to disguise your pregnant/trying for a baby

Katie • 27 years old, married
Hi all
​I'm actually in tww but hoping to be pregnant and want some good ideas on how to get out of drinking at a party without making it obvious we're trying for a baby. My friends all did the 'I'm on antibiotics and can't drink' excuse and I feel il be seen a mile off if I try that. 
​Any other good suggestions?! The party is this Friday and I won't find out for definate until Saturday if AF shows so want to be cautious!