In that case... you should stop messaging him and trying to call him. The signs are not good, from the looks of it, he wants to cut out all contact with you. For how long, or why, that I don't know, but if he's trying so hard to avoid you, then going after him isn't going to solve anything, short of appearing at his doorstep (which would make you look clingy, if you care about such matters). If it's a passing matter, then he'll eventually contact you back. Or maybe he won't, and you should take that possibility into account. Either way, no matter his reasons, him making you go through such a big emotional distress is not ok, he should have definitely told you something about it, and personally, if someone did that to me and then came back, she better have a damn good reason.
It is still possible that, yes, he has a very good reason to do that to you. And then, respect that reason and wait. But he could also be breaking up with you in a most cowardly way (I'd heard that breaking up through the phone was bad, but at least they have the guts to say it, even if not enough to do it in person. This one would take the cake). And if he's doing that, well... it would be time to start moving on. I'm sorry. Either way, the best course of action is the same: stop trying to make any contact.
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To build may have to be the slow and laborious task of years. To destroy can be the thoughtless act of a single day. - Winston Churchill