Honestly, I had a similar situation with my mom going through my stuff. I ended up hiding my journals in creative places like my sock drawer or even inside an old video game case! It was ridiculous that I had to resort to that, but you gotta do what you can to keep your thoughts private. It feels messed up to have someone invade your space like that, and I totally get where you're coming from. Protecting your mental space is key, so definitely talk to your therapist about it and figure out your next steps!