Slept with my cousin

It was a night last summer. My family and my cousins family (my cousin, my uncle and his wife) where on a trip together. All the parents were away so me and my cousin were alone. We got bored so we took some of my uncles alcohol. We said we would only take a little but we just kept drinking and got really drunk....
That night we had sex. It's not something we would do sober or anything so I can't help but wonder if this is wrong. Is it normal to have sex with a relative when you're drunk?