hugoagogo the shopping did it for me as well. Mine went Saturday and when I went to do my weekly shop yesterday, I just found myself picking up and putting down all the stuff I used to get for him - even saving me £40 didn't cheer me up! Only child as well (although do have SS but he won't be over now for 2 weeks.
It's a very weird time - first time ever me and DH will live together without children being resident (we both had DC's before we met). I keep trying to think of the positives and the new adventures for me and DH as well as DS but I keep putting off going home today as I know it is a very quiet house I am going back to.
On plus side DS messaged earlier saying he loved it, met up with flatmates last night and were all going to pick up wristbands later together so 2 days in he seems ok.