<human>: Can you give me the gist of the text in a nutshell?

Hey, so I've been working in my current job for about 6 months now. we're a small team of 5 and we all get along well, my other co-workers are all 23. It's a pretty stressful job, I have anxiety issues and generally jump to the worst conclusion.

One of my co-workers asked me last night if I'm going to go out for our bosses birthday drinks tonight (her birthday is not for another couple of weeks). I said I hadn't been invited, co-worker insisted that our boss had just not been able to talk to me about it yet. He said that If i was intentionally not invited then he would also not go because he feels its unfair to exclude me. I tried not to let it bother me, I figured she had all day to text me today if she wanted to invite me but I never heard from her. Co-worker messaged me just then explaining that our boss said she didn't invite me because I have the early shift tomorrow, he told me where they are going and that I'm welcome to join. 

Being the paranoid alien that I am, I cant help but feel like I found out by accident and that I'm only being invited now because she knows I know about it. I feel super crap that I've been left out and that I haven't heard from my boss personally. I also feel like maybe it was planned this way so I couldn't attend. I feel like that is a shit house excuse because I know she has gone out drinking the night before work too. 

Is my bosses excuse to not invite me out to her birthday drinks because I'm working tomorrow acceptable?
<bot>: My boss didn't invite me to her birthday drinks because I'm working the next morning, I don't feel like that is a very believable excuse.