Please help! 6month old baby

My son has been crying around the same time everyday and it’s using while I’m cooking and my mom has him. I will stop and come get him to try and feed him to go to sleep but once I get him a starts crying even harder, refuses to eat and I am unable to console him. I rock, walk, sing and he’s even breastfeed. But nothing seems to work. Then my mom comes and gets him and he stops crying instantly. I’m really sad and don’t get why he doesn’t want me or what I’m doing wrong?