I have two girls - one 2.5 years and a 9 month old baby. They basically get on pretty well - smiles and tears and they seem fond of each other. However over the last 2 weeks the older one has started grinding her teeth every time she approaches her little sister. She might be saying something really sweet or offering her a pretend cake but her jaw is clenched and her teeth are grinding away. She doesn't do this at any other time. I have been known to grind my teeth when I'm stressed and even though she seems pretty happy I'm worried that she's hiding how stressed she is by the baby while hoping it's just a phase. Has anyone else lived through anything similar? Thanks!