First off, most girls are on their phone from morning until night, and she probably just cleaned up the area and put your slippers were they should be. Your being a little paranoid don't you think? You could be right, you could be wrong. Either way, stressing out about isn't going to get you anywhere.

So, first things first. Calm down, take a step back and is that who she is? Is that apart of her character? I think the best thing you can do is ask her, and take her word for it. If she gets mad tell her something like "I just don't want to lose you" or something like that, make it romantic, very easy [I have done this].
If she is, just place your trust in her and it will come out eventually. Just try to stay emotionally detatched from her until you know for sure she isn't. Don't go snooping or doing anything like that, just trust her. You don't want to mess up something good. I say take it easy.