I think my boyfriend takes me for granted.. what should I do?

Hello.. I’ve been together with my boyfriend for a year and four months.. we’ve talked about commitment and serious stuff already and I’m so much in love with him.. the thing is that lately ‘ve been feeling like he just takes me for granted.. see right now im really studying hard to graduate from law school..which keeps me pretty busy during the week, the thing is that im always calling my boyfriend, he never calls me!!! im always like saying sweet things to him and being supportive with him abou his job issues, I even go to his house and spend the night there like once or twice a week, and whenever he needs my help i stop doing whatever im doing and run to be with him.. ok so.. am I doing just all wrong?? why wouldnt he call me.. last time he went out of tow to visit some friends for two weeks and never called me .. not even once..i did talked to him and told him i was kind of hurt because of that.. i dunno.. what should I do?? it sucks since im so stress about my barr exam and this whole thing puts serious stress on me and my heart.. should i just back off without saying anything and just focus on my thing and wait for him to reach me??