I feel as if I am about to have a mental breakdown?

A friend of mine disappeared exactly a year ago today. We talked every single day for over a year and he disappeared. He had just moved to a different town. He had many names, none of which were real, but I knew him better than anyone. I've never been as close with anyone in my life. He disappeared and I find that I'm going crazy. I imagine he is still with me, that we are going out to dinner together, that we are chatting over brunch. I cannot handle not knowing. I have been going through obituaries from the past year looking to see if there are any young men who fit his description but to no avail. I don't know what to do with not knowing, how do you deal with that..?