my mother is driving me insane

Katie
My son is 7 months old, the first couple of months things were fine but the last couple my mum has completely taken over with my son. When I visit or she visits me which can be nearly every day I literally can't get to him she is just in his arms all the time. If he crys I say here il take him ( because He is my son and I want to comfort him) but she ignores me and Carrys on. 
Iv heard her calling her self mummy several times when I'm not in the room 
She is always correcting me on how to do things.. like bloody holding him :0 he's my son Iv looked after him everyday for 7 months I no how to bloody hold him.
The other day she was like I need to talk to you. I don't like Daniels name we need to get it changes... ahhhh I could of screamed but I just said no Daniel is his name like what the fuck. 
She makes out in front of people that she knows how to look after him better than anyone. 
I love that she loves him so much I want him to have as many people in his life as possible that care for him but I'm getting really down and upset and even started to believe I was a rubbish Mum because of all of this