Absence of dad. He's mentally affected.

Hi doctor.. I'm 27 yrs old. My son is 2yrs 9months and my daughter is 2.6 months. I'm here in my parents house for delivery of my second baby since September. My husband is very close with my son. He was here till my second baby was born and now he has gone to the US for a period of 2 months. He will be returning by Jan 2nd. Till now my son dint ask much and even if he does I would say he has gone to office in a  different place. n he would bring lot of toys once returns. 2 weeks back I went to my house which is a few kms aways from my parents place he was disappointed that we couldn't stay there or I don't know whether he thought that his dad was coming from office (that would be the routine). So from them onwards he's been acting weird. Very cranky, hitting others, throwing things. Normally he's a very well behaved child for a 2 yr old. and every night before sleeping he silently cries and asks for his dad. Now I'm stressed whether he's mentally affected.