Overreacting?

Lakota

My fiancé’s birthday is coming up soon. We didn’t get to be together last year for his birthday because he was away at Job Corps in another state. So I just assumed we would be together for his birthday this year. (Since we also are living together and plan on getting married next July) but today he told me he was planning on going out drinking with his friends from work (which I don’t really like but that’s another story) so at first I was like okay cool; thinking I was invited. But then he started talking more in detail about sleeping arrangements since he plans on getting pretty drunk and we live about an hour from any good bars. That’s when I realized I was not invited to his “birthday drinking bash”. Should I be upset, worried, or am I just overreacting/overthinking?