C.L.
Please don't stop nursing him. That will most likely make things worse. My son had a really hard time weaning at 14 months. Your son needs the comfort of nursing, especially right now. Does he have a favorite comfort item you could leave with him? I would say just keep trying and exposing him to other people. Maybe do it for shorter periods of time and gradually increase the amount of time you are gone. I work in a church nursery and it is also best if you say a quick goodbye and leave--don't linger, but also don't sneak out. Good luck.