Should I Drink?

I have a mate's wedding in a week but we're trying and Im Ovulating this week. That means the wedding is a week before my period is due, so there's a chance I could be pregnant but not know it.

If I do a test a week before my period is due, will anything show?

I clearly want to be able to drink at the wedding but I dont want to be too selfish if theres a chance I might be pregnant.

Please help?!?!?