How do i make my bf know that i really do like him...?

me and my bf have been dating for 4 months.i don't know how to make sure he knows i really like him because he always calls me first because im afraid he will be busy or something when i call and plus im too shy to call.and,whenever he does call he always says 'bye,i love you" first.i dont want to tell him bye,i love you when he still wants to talk more!.and something else is,i don't ask him questions because it makes me feel nosey.i was just wondering if that made him wonder if i really liked him.and if it makes him feel like i don't,how could i let him know that i really do like him?thanks for help!-----Keely