You're going through rebirth pangs - it is always painful to realise cherished and comforting beliefs are just human fancies
For me it was more personal than than just losing faith in a belief system. I adored my grandfather, wanted nothing more than to have him back with me in a paradise. I was also an identical twin, with a brother that died at 2 weeks old in Kabul Afghanistan (we were born there..I lived, he didn't). I always wondered what it would have been like growing up with him - we were exact copies of each other. I used to daydream about him coming back as an infant, and my wife and I raising him like I did my own son (who is 18 now and like me, out of the borg).
Real life set in, and that sure was sobering, to say the least....