Am I being irrational?

Katie
So my sister in law is making me upset because it is her way or the highway when it comes to hanging out with my son, and I am told I am to controlling and I need to flow more. When she watches him, his nap times get all screwed up, if he sleeps over, his bed time gets screwed up and she usually ends up waking him up at the crack of dawn so she can go work out and then drops him off in the child care center. Mind you, my boyfriend is the one that asks her to watch him and tells me to calm down and that she is just doing us a favor. I tried asking her today if she could hang out at our house for a little until he wakes up, because my boyfriend asked her to watch him when I went to work. And she flipped out on me and said she can't wait til I have two because then I will finally understand how ridiculous I am being, and said he needs to be up and ready when she gets there. And then she had my boyfriend call me to get mad at me too. I don't know if I am being irrational and if I am not I am at a loss on how to talk to them about how I feel. I am looking out for the best interest of my two year old son, and when his sleep schedule gets messed up then I have to deal with the aftermath, not my boyfriend and not her. I'm just frustrated and needed to vent but I don't know how to talk to them about this anymore.