A Night of Impulsiveness at Work

So, I recently broke up with my long-term girlfriend of five years. It was tough but necessary; we just weren't growing together anymore. She wanted kids, and I wasn't ready for that commitment yet. We're both still adjusting to being single again. This week has been pretty uneventful at work. My team is handling a big project deadline next month, so everyone's heads-down focused on the tasks. I'm just kind of coasting through it right now, trying not to think too hard about anything. Last night was when things got... interesting. I had an email from my ex girlfriend saying she'd be in town for the weekend and wanted us to get together again before moving on. It made me conflicted, but also kind of excited at the idea of seeing her one last time. I didn't know how to reply so I just closed out my computer early and went home instead. But on my way out, I ran into Mike from accounting in the elevator. He's single too after breaking up with his wife a few months back. We struck up conversation and ended up talking for quite a while about our situations. Then somehow it turned to me asking if he wanted to grab drinks later since we were both going out of town this weekend. Long story short, we ended up getting really drunk at the bar. I know that sounds like the start of something silly, but it wasn't exactly... We got back to his place and he asked me some pretty personal questions about what I wanted in a new relationship. And then... well, let's just say things progressed quickly from there. It was unexpected and definitely not part of the plan for that night. But now I'm left wondering why I did it - is it because I still have feelings for my ex? Or am I actually ready to explore something new after all this time in a relationship? Why me, why now? It's all just swirling around in my head right now and I don't know how to sort out where things go from here. I definitely didn't expect that night with Mike to lead anywhere serious. But then again, maybe it did and now I have to figure out what this means for me moving forward.