My son prefers his grandmom


I have a son who's turning four now, and he prefers his father or his grandmom than me,and special now he wont even let me touch him, i live with my mom so she's the one who changes his cloths put him to bed feed him coz he wouldnt let me touch him his father is away for now,but i feel like im a bad mom, i dont know what to do i need your advice ladies, please help

Update: thank you so much you guys, im currently not working but i have a 11 month baby girl and he's a little bit jelouse about her and my mom treats him more even gives him the babys toys and she always tells me she loves him more.