Sorry to hear about it.
I've had it happen to two people I knew, both at a young age. I just wandered around in a stupor for like a week. Make sure you eat enough food and stay hydrated. Both times, I had no appetite for quite awhile.
It's quite a blow, and very depressing. For the first few weeks, everything seems kinda pointless. Talk to people about it. (which is what you're doing already, which is good). Just give it some time. Eventually, you won't be sad about it, you'll be happy for the time you did spend with them. That whole thing about loving and losing being better than never loving at all, it's true.
I'll give you some background on my story.
Back in April '03, my aunt had kids. My aunt and uncle really liked the kids, but my uncle had a hard time dealing with the pressure. Before, he was always pretty relaxed. I think part of it was that he didn't have kids until he was 39, at which point, having few responsibilities on the family aspect were very ingrained in him and my aunt. I had spent weeks staying with them before, and it was very quiet. They both had big corporate IT jobs. They would come home at 6, have dinner, then spend the night just hanging out. Weekends would be a three hour drive to the grandparent's house in Vermont, then two days away from everything, skiing in the winter, boating in the summer, etc.
Then kids came and it was like, WHOA. All that free time you've had over the past 21 years, since when you moved out = gone.
Now he had to be tight and wound up. It didn't help that my aunt was very unhappy when he wanted some time on his own. Started hitting the bottle waaay too much in Fall 04. Keep in mind, most of the family is alcoholics, (I've seen family photo albums where in nearly every picture, they're holding a beer can, or a bottle, or a red plastic cup) , but this was very heavy drinking. We're not talking shots of vodka, we're talking pints. I think all in all, he went through like three quarts a week. Also to be noted, he has had stomach problems his whole life, including an ulcer, and has become diabetic.
December 05, he wakes up, eats breakfast with my aunt and the kids, my aunt leaves, the nanny takes the kids, and my uncle goes to bed for three hours. One day, he says he's feeling really bad. Goes to the hospital. He's in a half delerious, half comatose state for weeks in the intensive care section. Alcohol has pretty much fucked up all his digestive organs. The doctors said that even if he survived, his digestive system would be so fucked up that he wouldn't be able to eat half the foods he liked, and even the smallest amount of alcohol could kill him.
He started to get better in March 05, but was still pretty delerious from being in the hospital and under medication so long. Around this time my aunt found out that she was pregnant with their third child, and the twins are about 2 years old.
Late March, he started to get worse. There was a lot of internal bleeding that they couldn't stop.
His entire digestive system was a bleeding mess. Early April, it got very bad. He was losing blood as quickly as they could pump it into him. He didn't make it.
His third daughter was born August. She won't ever get a chance to know her dad. He never even knew she existed before he died. His twin daughters were not even two years old when he died. They will probably have only faint memories of him.
That sad enough?
I could go on with some more details, but it's late, and I need to go to work early tomarrow, and I don't know how much more I could write right now. You kinda forget about it after awhile, remembering only the good things, and not how horribly sad the last 6 months were.