How badly did I screw this up?

Yes you did screw things up, and you know it. You not only disrespected him at the bar, in front of other guys, but you didn't even have the decency to turn your ringer off or turn off your phone while you were hooking up. Why did you have to text back just then? Did you have to make it so obvious that he wasn't important to you? He' s gone. Someone else liked him and he's thinking (rightfully so) that he should give this person a chance now.