Dating advice for long distnce rs?

He loves me, but he's always busy.. he just replies to me and tells me he loves me. I'm the type who likes conversation and loves to have communication... Talking with him makes me really happy... But we can't talk long as he's never avl/free. I usually go along w it and try to be understanding.
But recently he didn't talk wimme for 3 days straight... I mean, no matter how much busy someone is, how can they not even text a single message to their partner?(on a sidenote, it was his exam week) i dnt talk long with him anyways, his little replies are enough to keep me going, but when he disregards me like this, i feel like he doesn't care for me at all.. i texted him again consecutively.. but he didn't reply.. on the third day, i got worried and called him up(i dnt do that bcoz of having strict family) he texts me asking what's up... I felt soo irritated.. i broke down crying and told him if I need a reason to even call him up now. I told him how he should've informed me at least. his exam had ended the day before
. I was frustrated.. i sent him couple of texts being furious and told him I won't text him till his exams are over. For a week, i didn't text him.. (actually i did but deleted them all) and neither did he text me at all. Last night i was overthinking and cried while i thought of how we didn't communicate at all for the past few days...i texted him. Deleted it again. Maybe he saw my text.
He replied a while later saying he'd call me up tomorrow (that's today**) on a whim, i said "it's alright..dnt bother" and "good luck for ur exam"
He didn't text me back, kept me on seen... That was it...today was prolly the last exam... I'm not sure.. i was really overthinking and crying too much so i ended up givng him a call... I cut the call. I went for another try, but i was too afraid that he'd pick up, so i cut it again. He said, "now what" "u told me not to call u"
And i just said "sorry"... That's it... I couldn't muster up the courage to say all those emotions I've swallowed up. I have test on Saturday, and sadly can't focus on it at all bcoz of all this emotional turmoil I'm going through... Am i the one who's at fault for not understanding him? Am i the one who should ask call him n apologize properly? Maybe i was being too clingy?? Does he not like me? What's wrong???