Help!!

So we just found out we are pregnant today and I think I’m about 4 ish weeks along. I haven’t missed my period yet but got a BFP on a clearblue digital test. I am going to a bachelorette party this weekend where I’m the maid of honor and I haven’t told anyone yet. How do I not drink without spilling the beans about my pregnancy?? We don’t want to tell our family (let alone friends) until after the 8 week appointment which is Dec 13. What do I do???