My ex-husband and I have been separated for 3 years. My son is 4. Our visitation schedule has changed several times over the past 3 years.I have battled his strong will that gets even stronger with each change. Son becomes angry, cries easily,overall EXTREMELY DIFFICULT. Most recently, his dad went to an inpatient rehab center for drug addiction for 2 months. First 2 weeks were AWFUL. Then he adjusted and did better than he has ever done. Dad came back into town this week and my son is back to being an emotional handful. Is this normal for a kid this age to react this way? I need some help, please.