If you were me?

So AF is 2 days late never happened before! Regular as clockwork normally. Now here's the problem I've tested and got BFNs this Saturday is my hen night obviously I will test sat morning if she's not showed up but should I drink if I'm still getting BFNs? Obviously it's going to be hard to not drink without people noticing I just don't know whether if by then I should presume I'm out this month and just have a good night out with all the girls?!