Breaking down

I hate when I'm having such a good time and am able to be positive then something happens and it triggers something on my mind that just throws me off my axis and I break down and just lose my mind. This happened to me Friday evening down at Rabbits. I was completely fine, minus a few drinks, and it just hit me like a wave. I just started crying and broke down over my friend, I don't want to lose him but I know it's not my decision. I don't have any way to stop the inevitable. All I can do is be thankful for the time I do get to spend with him and take nothing for granted. I just don't like the feeling that I could lose him any day. This is going to be a really difficult 4 years for me, and even harder after he's gone. I just don't know how to handle it all. I've never been in a situation where I know I'm going to lose one of my best friends to a medical condition and he's so young also. I just don't know how to feel or act and I don't want to hurt inside. I really need comfort and my other friends around me in this time of life and it's trials...