How do you tell your d.i.L. that she makes you feel uncomfortable while playing with your grandson?

She hoovers over me like I am going to do something wrong. I cannot pick him up due to a bad back, but I can play on the floor with him and his toys. I can hold him on my lap while sitting in a chair also. When she sees him playing with me and being happy, she usually tries to get him to come to her by holding up something and he will go to her. Then she picks him up and walks away with him, or she will say, " you stink lets go change your diaper. " Then she doesn't come back until sometime later. She does this numerous times through out the day while I am there (usually I have just 4 to 5 hours) then I must travel back home of which is 2.5 hours away. Is this my imagination or what?