The best thing in this situation is patience. You are the most important thing in his little world and after being with him constantly for 13 months, he gets scared when you leave him. I know he has a Daddy there too that loves him very much but you are mommy who feeds, hugs and loves him day and night 24/7. This actually happens very frequently and I'm lucky that I haven't been through it yet with my 16 month old. When I go out the door she cries for a moment until she becomes distracted with something shiny and she is content to play with it. What you could try is that when you leave him with someone say,"Mommy is going for a little bit, but I will be back." Smile at him, relax and don't be nervous about how his reaction is going to be. The person you are leaving him with plays a very important role as the caregiver, they need to be constant with trying to make him feel better. This can be anything from giving him his favorite snack to playing with the most interesting toy (one with lights, sounds and vibrant colors) or playing one on one until he can finally relax and know everything will be okay until you return. He needs this attention until he stops crying and whining because he needs to learn that when you are gone things can be fun and it's okay to play without mommy there. Maybe Daddy can find something special that they can both do just for the two of them while you are out. If you have two cars have your husband take him someplace fun. It is very important that he isn't let to just cry it out when you go, that only adds to his feeling of overwhelmed loneliness. When you do get home, shower him with kisses and hugs, I'm sure he'll be excited about seeing you and run to you for them anyway. After leaving him for a few hours more and more, he will become much better at knowing that he's going to be just fine and that you will come back to him. Remember to stay calm, babies and children can sense your anxiety and it makes them even more nervous than they originally were. Be patient and compassionate, but do not let his behavior rule everything you do, you are the parents, you teach him what the best behavior is and with persistence and cooperation with who you leave him with, he will learn and understand that everything is going to work out just fine. Don't worry, you can do it. Good Luck.