There's a lot the inevitable "love is all bollocks, grow up" talk coming from blokes who sound like their hearts have been broken beyond repair.
The thing is she could be being truthful and just be off out with her mates and busy tonight, does miss him like she says so if that's the case you don't want to overdo things in a rush or things can go awkward very quickly for both of you. On the other hand if she is trying to be "nice"(which lets be honest is not wanting to do the right thing for fear of feeling bad) and telling him basically all the wrong things, it's not him that needs to grow up or grow some... really annoys me when people do the "take the hint" thing when in actual fact they were so cowardly that they didn't give any real "hints"(if you're the only person in the world that can decipher it then it's not a hint), which usually results in things coming to a head and making the person on the receiving end feel like the biggest dick on top of the bad news/disappointment.
You could delete if you feel your will power is waning she can always contact you if you are wrong and you will know who it is straight away even by text most probably, if they ask why you didn't call you can just say it felt like she wanted you to give her some space so you did.
It does sound like she doesn't feel the same way as you do though so you might want to think what's best for yourself before your feelings deepen any more. I could be wrong but "kinda single" does sound like she is seeing someone else but it's just for sex. You could remove feelings from it and keep it as friends with benefits or maybe watch some kinky cuckold movies and try and get into that way. Probably not what you wanted to hear this last paragraph I know.