HELP! Answers preferably from you men (well...and ladies if u can help me!!)?

Basically there's a likeness between me and this guy. He found and added me on facebook, we've chatted and was nice, I sent him a quirky lil message with my number. Then he replied giving his too! Excellent! Left it a wee while 'til there was any contact - didn't wanna seem too interested. Now on Friday i was going to this club and had a spare ticket, so i thought hey i'll send a casual message offering him to come! Unfortunately he couldn't make it, to be fair i asked in very late notice but he thanked me and said it was pretty cool of me to invite him. And texted a bit, then later that night said hope you're having an awesome evening will call you about those drinks and bla bla bla.......it's Monday and being a typical girl i'm getting all impatient because i fancy him like mad haha. He's in a busy job, got a lotta stuff goin' on that i'm sure about. So maybe that's why he hasn't messaged yet... but what do you think if i sent him a little message saying heeey i'm free "this night" if you're still up for those drinks. I dunno something along those lines.? Say it in a cool way you know so it doesn't sound over keen. I just kinda wanna get the ball rolling a bit and he's super hot. Haha sorry but i really don't know what to do! Do i leave it and wait for him? He's a busy bee i don't want him to forget me! I don't wanna screw my chances. Any advice?