Stuff that freaks me out...

So... last night around 3am I am awakened by a strange noice out in the living room. I finally decided it was the cat up to something. So I decided to go out and check on her. Anyway, she has recently had her front claws clipped and she appeared to be trying to dig her claws into the top of the couch and I think she was a little freaked out that she had no claw there so she was doing it over and over and it was making this strange noise on the material. So I pet her and she was all happy to see me as usual, purring and stuff but Willow, I have to go back to bed. Talk to you in a few hours. So go back to bed. Get up this morning a little after 6. The front door to my apartment is wide open. So.... like I'm totally freaked out. (Also glad she didn't decide to venture out although I don't think she would have made it far). This is the inner door inside the apartment so its not like it was opened to the street or whatever. You go downstairs and then to the door to the outside. But yeah... anyway, completely freaking cause the door was closed when I went to bed and it was also closed when I got up to check on the cat. So I'm guessing - or more what I'm hoping - is that the door wasn't completely shut or whatever and opening another door in the place created a draft which popped the front door open. And, lets face it, that is probably what happened - I've seen it happen before - plus the door expands and contracts so much lately in this varying weather that sometimes you really have to pull hard to even get it to shut - its weird. Regardless I will now always be deadbolting but still... part of me worries that maybe someone was trying to get in or something and that was what caused the cat to start acting all weird and they bailed when I got up. I don't know... I hope that wasn't the case. The door doesn't seem damaged and the lock was still "locked" even though the door was open. Freaky freaky stuff!