Mother in law has good intentions but...

My mother in law is not nurturing to me at all.  I mentioned something about my back, and she said "your not even that pregnant" with a toughen up additude. I'm 20 weeks, and at times uncomfortable and it bothers me. She talks about her pregnancies as being perfect and questions my desision to give a water birth. I'm trying to hard to be sweet with her, and accommodating, but she's seriously pissing me off. It's the first grandchild, does she just not remember? Do I just need to suck it up and be patient?