I am seriously so fed up. My boyfriend's mom is driving me insane. She acts like she's the mother of…

I am seriously so fed up. My boyfriend's mom is driving me insane. She acts like she's the mother of my baby. She watches me like a hawk every time I change him and he cries because he doesn't like being changed and she goes "oh he doesn't like that, pick him up." Or she tries making me feel bad about my son not gaining any weight (he is almost a month old and he still isn't back up to his birth weight, and yes I am already frantic and worried about it), implying that I don't feed him enough when he eats every 2 hours, sometimes sooner. And I laid him down for a nap today and she told me that he's sleeping too much and the second he started crying she went to pick him up. Honestly nothing bothers me more when someone tries to tell me how to raise my baby. And I've already talked to her about it several times.