Mother in Law wants to bring up my baby!

Iram
My 3 week old boy is the first grandchild in my husband's family and ever since he's been born, my MIL keeps insisting that I stop breastfeeding so that I can drop him off to her house everyday. She says she wants to bring him up and be his main carer and she's annoyed at the fact I breastfeed, as it means she can't take him to her house whenever she wants. 
Needless to say, I hate the idea of leaving my child with her! I feel so protective about him and whenever she has him, I feel like she doesn't know what she's doing.
Whenever she comes to see him, she hogs him and every time he's hungry she will try and put him to sleep because she doesn't want me to hold him and feed him.
She also shoves her hot water bottle on to him and I feel that he's always overheated!
She's also always commenting on how he's not chubby enough and she thinks he's not being fed well.
I get so scared with many things she does but I'm not the type to say anything. It just frustrates me so much!
I'm struggling with breastfeeding as it is and this whole situation really isn't helping.
Just needed to vent tbh, as I'm too much of a pushover to actually say anything to her.
I know she loves him as it's her first grandchild and only does all this because she cares, but it's my first child too and I think she fails to understand this!