where is the line?

Tonight, I'm going to dinner with a friend of mine whose birthday party I missed because I completely forgot about it on the day of. I sent him an email the day after, apologizing profusely (and very lamely) but offered to take him to lunch. He emailed back, saying that since had also missed my bday party (he was sick), we owe each other a meal, so how about sushi sometime at this place he knows downtown?

He then wrote a PS: "So I noticed you were originally down for 2 people [for my party]. Were you going to bring a boy and try to make me jealous? At my own birthday bash? That's so mean. I don't think this is going to work between us :)"

I was going to bring a boy; I was going to bring RC, so I wasn't sure how to answer that question, or whether or not to even acknowledge it at all in my reply. I ended up writing that sure, I'm up for sushi. "When are you free? I'll have to check my calendar, and of course, that of my gentlemen friend :)"

I don't think my intentions were to be vague and ambiguous, but I just thought saying something like "yeah, I was going to bring my boyfriend" would have been really awkward, so I made a joke out of his joke. Maybe I should have just not acknowledged it at all. I was also plagued by the feeling that he was perhaps trying to make a date out of this.

So he ended up making reservations at a sushi place for tonight at 8:30pm. He just sent me an email asking if we're still on for tonight, with the addendum, "The sushi restaurant is downtown, how about I swing by your place around 8:15, and we can take a cab there? It's a reasonably swanky place, so I can't imagine you'll want to walk if you have heels on."

I don't know if I'm reading too much into this. Does he see this as a date? Am I just paranoid in thinking that guy friends who want to go get sushi at a swanky sushi place is looking for a date? Why can we just take the subway? Was this also a hint that I ought to dress up and wear heels?

I don't really know how to handle this situation. Have I already gone too far in somehow leading this guy on? I told RC that I'm going to dinner with this friend whose birthday party we forgot about, obviously not hiding anything, but also I'm not telling him the whole complete story, too...

I think I'll offer to drive, and pick my friend up and go downtown via car.