As a rescue volunteer and foster home, I see this all the time. 
If you've reached the difficult decision to surrender your dog, it sounds as though you are thinking carefully about your dog's welfare - always the first priority. I firmly believe that rehoming can be the best option for a dog when people's circumstances change dramatically, often through no fault of theirs. Bereavement, serious illness, relationship breakdown and job loss can all be valid reasons.
Sometimes it's possible for a charity to keep you in touch with the dog you have surrendered. We do this with two of ours, and provide regular updates/photos etc.
One of the most moving relinquishments I've ever witnessed was a lady who had terminal cancer. The rescue were able to find a lovely foster home very near by and kept her updated and with regular visits, and a permanent home was found after her passing.
Another one of our dogs is from a racing owner who died - he looked after his dogs, but after his death his family didn't want them. They ended up in the pound, but rescue stepped in. Our beautiful tiger is now a much loved member of our family, a gorgeous stripy squirrel chaser with the biggest brown eyes. Before she came to us, she was in emergency foster care, and the foster carer herself was utterly smitten. It's so nice now that as things have turned out, we regularly see/socialise with her previous foster carer, so she can see how happy and settled she is. When Tiger sees her "Aunty S" she gets huge cuddles, big licks and a storm of tail wags.
It's natural for the first few days to be a bit topsy-turvy, and of course your dog will miss you. But a good charity will take great care to place him in an experienced foster home who have experience and will help him overcome this period of transition. You may actually find that he really enjoys his "holiday" especially if he has new friends to play with.
Although dogs do remember their special friends, they are also very good at living in the moment and learn to form new bonds.