My BIL (39) is acting weird and is always in my (25 , F) business.

So let me just say that I love with my sister I rent a room 600 dollars a month plus I buy groceries. So I fully belive im entitled to my own business.
My sisters husband on the other hand snoops in my room, found out I had an vibrator then began questioning my sister about what other sex toys I may have, he always tries to ask me if I'm dating anyone and acts weird if I say i'm talking to someone or not. If he and my sister goes somewhere he always wants me to tag along to third wheel. I always catch he staring at me no matter what i'm wearing, he goes through the phone logs.
My sisters has told him to back off but still he persist.
What should I do? I can't move out yet due to the caronavirus pandemic but i'm at the end of me wit.
Tl:dr: my bil is weird as ****.
Ps: I do have a lock on my door and I keep the key with me 24/7


Source.