I'm really sorry for your loss. It was clearly a significant one. To expect to be "over this" in a matter of a few months (let alone two weeks) just isn't realistic. Take it easy on yourself, and give yourself whatever time you need. Everyone grieves at a different rate. You may feel this loss for a very long time. But, it will get better and easier to handle as time passes.
Sometimes doing something concrete can help. I don't know what will appeal to you, but visiting his gravesite might help. I'm guessing he wasn't completely alone in the world, so maybe writing a letter to one of his loved ones -- parents, siblings -- telling them how much he meant to you would help everyone involved. Maybe you can think of something even more appropriate, given that you knew him so well.
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Put the curse of loneliness on every boy and every girl,
Until everybody's kickin', everybody's scratchin',
Everything seems to fail ?
And it was all for the want of a nail.