Update: We had a security system installed today. To much weirdness for my liking. Especially after I discovered that one of the "windows" on my crawlspace had been removed and was propped up against the house. I don't know exactly when that happened, but I know that my DH installed it in the fall and up until a week ago it was covered by a snow drift.
I talked with neighbors, friends and family and no one popped by that day unexpectedly. So unless I am losing my mind and didn't go through my normal routine (twice) like I remembered doing, someone that I don't know what in my house using my washroom....
On the weekend my DH the kids and I went to visit friends for the day. I went through my routine before we left. I made sure that the dogs were locked up in the kitchen/dining room. I made sure the doors to the bathroom and DS's room were closed. I checked our sunroom to make sure our cat wasn't in there and closed that door too. Then I double checked everything before walking out the door (because I'm crazy like that).
When we arrived home I came into the kitchen and the first thing I noticed was that the puppy had gotten into the garbage in the bathroom and dragged it out into the kitchen. Hmmm, I'm positive that door was closed when we left. Next, I realized that the cat hadn't greeted us as he normally would. DH opened the sunroom door to find him waiting to be let in. Again, I double checked before we left to make sure he wasn't in there (no litter box in the sunroom and I hate cleaning up cat messes).
So, now I am convinced that someone was in our house. It makes no sense, I know. Why would somebody come into our house to use the washroom? But I can't get past that feeling and it is bugging the crap outta me. Usually we leave the back door unlocked (we live in a very rural area and it has never bothered me) but now I don't want to leave them unlocked even when I am home.