I shouldn't have come home

I'm a college student living in an apartment with my sibling. I had a night class that was cancelled and I was going to take the bus home but I thought I would surprise my sibling and come home early. Both of us have keys to the apartment but no one else does. The only thing is we usually don't come home until 6 and it was about 3 so I was surprised to see the door open. Thinking it was my sibling I walked in and I noticed the tv was on and dishes were in the sink but no one was there. I looked around and nothing was wrong until I noticed a chair moved out of place. Now I'm freaking out thinking that there was a break in or something so I check my room. Everything is fine until I see a note on my desk that says "I'll be back, and I'll be ready" with a lipstick stain. I grabbed my stuff and went to a friend's house and called the police and my sibling. It ends up whoever it was used my key and probably found it after I lost it for the night at a bar. The police took my key and said they'll check for finger prints and the only thing is my key was in my purse and it has no pockets. My sibling and I are staying with friends until we get new locks and stuff. I'm just so glad nothing bad happened and we both got lucky.