Does he really love me? does he really feel anything for me?

i am 18 n he is 25. we are in a relation from past 4 years. the extent of love i do to him is far high from the power of imagination. Of late he is very busy with his business and he hardly cares what i feel. we live in the same city but we meet once or twice a month only though we have a talk almost every half and hour one hour. He is very supportive regarding my career and i too support and understand him and his business. I demand almost nothing except a little love and care from him n info a short talk after short intervals. I have a very bad habit of calling him continuously if he does not receive my calls. this is the reason why he gets irritated and shouts at me. He says even his family is irritated because of me calling her again and again. But what should i do? I get really tensed and worried if he fails to receive my call especially in the night. I have to wake up early in the morning but still i cant sleep till he goes back home whether it be 3 in d morning or 4 and i have to wake up at 6 each morning. i guess i am failing to give him space and this is the reason for his behave. cant he understand me a little if i do him always. i try to do whatever he wants to. i live my life on his terms but he hardly cares. he doesn't have time to hear me my feelings. he is never concerned.. its always about him. he has to sleep, he has to work, he has to eat, he is busy, he is upset, he is tensed, he is not well only he. i sacrifice all my comforts for him. he hardly cares if i m happy or upset, if something is happened with me or not, he has time to hear all i have got to say. does he really love me? i feel it wont make him a difference even if i take a leave. its only me who will cry. though sometimes e is really sweet but its only when he is feeling good. not when i want him. when i need him he is never there. he will leave me crying and go off to sleep. he wont call me back if i say him don't call me.he does but after a long time and i forgive him each time because i love him. how long will it continue like this? the gap when we don't talk hurts me more than him.i keep crying and waiting for his call. i want to get out of it? how to make him realize how much and how crazily i love him. will he ever love me? does he love me? does he care? is the age difference the reason? am i overreacting? should i move on? each time i think of moving on he does something really sweet and i cant help but stay with him. i too find reasons to be with him. its really gonna be very tough for me. whats wrong? i cant understand what should i be doing? am i really very irritating? i love him a lot is this my fault?