feeling sick to my stomach

Why is it that when I decide that I want to try and make things work with my parents, and that I want to trust them, they go and pull shit like what they did yesterday evening? 

I have my grades and other educational information set so that a limited number of people have permission to access it.  Amongst those I have excluded this year are my parents, because I wanted to start holding myself accountable for my actions in school, instead of having to answer to them every time I fuck up.  They went behind my back and accessed my information somehow.  I'm not pissed that they saw that I'm having trouble in a few classes, I'm pissed that they went behind my back to get that information, when they had no right to be accessing it in the first place. 

Yes, I know I still live under their damn roof. Do NOT try and argue that point with me.  I want to be able to trust them, but if they're pulling shit like that, it shows me that yet again, I have no reason to trust anyone I'm related to by law.  I keep trying to not hate them. I keep trying to work things out with them.  But until they are willing to try and meet me half way, I am unable to bring myself to not feel feelings of despair and hatred towards them.  I do not like feeling that way towards anyone... Especially not the people who raised me.