Definitely pack the gym bag the night before with your work clothes (and shoes!) and lay out your workout gear too. I got a whole set of hair/bodywash, quick dry towels, and any other product I use so that it is always in my gym bag. Only way for me to consistently go. Even after about a year of doing it, I still wake up in a daze. Biggest downside, you will find yourself waking up earlier on weekends too.
It is a tough balance at work. We have both types of people and for the most part those who cut off conversations get labeled as rude or unapproachable. I think maybe the best bet is to ease your way into it. Make sure you listen clearly to what the other person says, and maybe respond with a quick summary (to show you are not being a jerk) and path forward. That is what I try to do to get away from long talkers (many of whom I actually like a lot but it becomes a time sink). I catch myself doing the same thing when I am not motivated to end a conversation. I need to work on that for sure. I think your coworker probably took it as an insult and obviously you do not want to come across like that. If you did not yet apologize it would be a good idea just to clear the air. Just explain you regret coming across rude and were juggling a few tasks/projects (too much on your mind). I think everyone has been there.