Do I do nothing and wait?

I met this guy the other day and things seemed to go well. Later the next day he messaged me saying he had a nice time and that he wanted to see me again soon if I felt the same way. I sent a response back the following day indicating my interest and suggesting sometime later in the week. That same day he also messaged me about going to an arts fest the next day but I couldn't go because of other plans. I haven't heard anything since and it's been a couple of days. Is he waiting for me to suggest something since he already did and I couldn't go? Do I wait for him to contact me again, and just assume if he doesn't he's no longer interested?

Ask him to do something so he knows you're still interested and weren't blowing him off when you said you had other plans.

I go with Jelef. Contact him and see what he says. If he doesn't say anything for a couple of days (2,3) you can assume that he's no longer interested.

He thought you blew him off.