Oh man, that was a close one. I know that feeling dude, I've had a few close calls myself lol
Always lock your computer.
Definitely shorten down the auto lock feature timer when around friends or family that don't know or understand.
Or maybe Mom would have been like, "You think that's crazy? Let me tell you about what I was doing in college. You know how they said on South Park, 'There's a time and a place for everything and it's called college?' It's true. Did you know your mother has a police record? Here's why…"
Or maybe she wouldn't. I don't know your mom.
Parents and family members all have a faux-innocence that means they think they can get into your things and 'accidentally' root around on them. Back when I was a teenager in the 90s, my own mother would log onto my account on the desktop, knowing ICQ was set to automatically boot up and log in, to 'accidentally' open my messages and see what I was receiving.
So I stopped ICQ from automatically booting up and manually logging in. Because she "accidentally" did these things constantly.
As soon as I did that, she stopped "accidentally" invading my privacy on ICQ, or logging onto my account, for that matter.
It's amazing, isn't it, how things stop "accidentally" happening when the reward for doing them, the serendipitious and "unintentional" benefit for doing it, goes away. Absolutely amazing.