1mg of Ativan 3 hours ago, can I drink?

I had a major personal event this morning and felt myself slipping into anxiety attack, so i took one that I have (as needed) at 1pm. But I remembered an hour later after I calmed down that I have a major music event to attend tonight and I wanted to drink for the last night of this event.

Can I do so? Should I wait until a certain about of time?