Very upset with myself

over the last few years i have not been myself to my loved ones.for the past few years i have been told my mom has dementia .at night time she gets up and walks around the house and i try to get her back to bed.which gets tough to do unfortunately yes i have been mean and have hurt her.now this really bothers me because i have never had her ever be mean to me.i do not know what is going on in me to do this and want to stop.