I Sometimes Can't Talk About Whats Hurting Me

So I finally broke down in front of my parents, a complete mental breakdown. they wanted to know what's going on and I told them about 10% of the truth. why can't I ever seem to open up and let it all go. why am I so protected. why do I have trust issues with everyone. I can't even come close to telling my sister, who is the one person I used to open up to about everything. sometimes I just wish someone would just force me to just be open but I know it won't happen, and I know I'd never open completely. then there is my trust issues, I could never tell a man, not even my dad about everything. I don't know why, I just can't. I could only open up to a female but I have trust issues. I'm in a catch 22 and it sucks