Help my mind ease

So my son is two. His father never really wanted anything to do with him but unfortunately he gets every other weekend with him. My son never wants to go with him unless my sons fathers mother is there.. half the time I don’t know where he is nobody responds to me.. Well for Easter break his dad gets him 4 whole nights instead of 2... I’m freaking out and stressed to death... help my mind get some ease plz 😭😭