Wow, that definately wasn't good. Out at a bar with your friends and when she is with her friends celebrating her new boyfriend's birthday is when you had a discussion about your relationship? Yikes. Talk about a worse case scenario. I wouldn't say that this helped anything towards your feelings and well being and the remains of your relationship with her. I know you were emotional and you felt like it was all pouring out and you obviously weren't ready for a run in. That's kind of the whole point of really working on yourself, so that you would be ready for the run in and be able to hold it in and keep your cool.
The best thing you can do is keep your cool and have a good time not worrying about her even if you are, keeping your guard up as much of a game as it sounds. You aren't ready to discuss it with her and you aren't ready to talk things out with her so nothing good could come of this.
I hope you feel a little better though letting some of it out after being dragged into it again.