Maybe he knows he comes across clingy so he tries not to pester you over the phone aswell. I love to give my girlfriend attention but I know I'd suffocate her if I didn't give her some space which confuses her at times too. Maybe that's all he's trying to do for you?
As the other guy said, best to ask him. Just be careful how you ask, if you ask as if you want to recieve messages then don't complain he's too clingy and now messages you all the time ontop of it.
He may be shy or nervous, or he may just be playing the game guys in general are hard to figure out. If he answers when you call then everything is okay and he may just like you. I don't know about the falling in love thing need more details. I can say though don't throw your heart out to just anyone and not quickly. Well that is my advice. And I'm sure that you could feel the love that he is giving you other than cuddling and clingy. Us girls have that type of thing where we can usual tell :-) Wish you the best of luck hunny, and don't rush love. Your in a young age group you have time :-)