my son is way to clingy

If you're a single mom, how is your son with you 24/7? Do you work? 

Little ones go through multiple phases of separation anxiety. My son is almost 19 months old and he freaks out around other people. He won't let anyone other than my husband or myself touch him. 

Your best bet is to get him more socialized. Take him to a park to play with other kids. Get together with friends in their homes. Part of the problem is probably that he sees your house as his territory. Since he isn't used to other people it upsets him to have strangers in his space. Start by getting him used to other people in a neutral settings and then he'll relax a little more at home. You should also have family members babysit him to get him used to being cared for by other people.