Difficulties with maintaining a proper eye contact, that is an impaired social skill, along with social withdrawal, excessive dependency, social inhibition, puts one at the risk for developing depression.
Depressed people tend to avoid eye contact, seldom smile or laugh, slouch, ask few question, seek reassurance from others and complain.
Inability for proper eye contact can be symptom of social anxiety disorder, too.
Cognitive behavioral therapy should be helpful in your case.
Best wishes!
Marija