Are you keeping a "signs he is into me" scorecard or something?
Just kidding.
Sort of. Seriously - it sounds like you are so concerned with how he
shows you he likes you that you are missing the fact that he
does like you. It sounds to me like he likes you, and that you two are having a nice relationship - not too deep, not too shallow. It may not be the deep, romantic "I can't live without you for an hour and must call you every day" type relationship, but it sounds pretty positive to me.
If you are concerned about him not calling - then call him. Nothing says you can't pick up the phone and say hello and ask about the party. No sense in putting yourself through such agony when it can be solved with a quick and easy phone call.
If you call and get the cold shoulder, or he just stops emailing/contacting you - THEN you can start worrying that something might be wrong.