L.G.
my son at that age cried when I set him down as well and went to do something... and I did not let him CIO until he was closer to 2- 18-20 mo. We had to take him from a crib to toddler bed or mat because otherwise he would have made himself fall out (very tall for his age)
Bring him everywhere with you... put him in a babyseat in the kitchen or wherever you are working so he can see you right there. Or better yet, if you can find a comfortable sling, get him hooked up in back of you... mei tei... or one of the many other back style carriers that are out there. After the stress of CIO at night he probably needs to feel close to you... give him that connection.