Jealousy of Drinking?

I'm 16 drink alcohol, not binge drink to get drunk or anything because I'm French there's a different culture to drinking, but I'm currently away from my boyfriend, who is 18, because of vacation. For the last two days in the morning he has told me he had been drinking the night before. I am very uncomfortable with it and it leaves me kind of annoyed. Why could this be? I don't want to be hypocritical but it leaves a bad feeling in my stomach