Can you please rationalize this paranormal?

Ok my door just opened by itself my grandparents are both asleep my bro is with me in the living room we heard a sound like a door opening so I got up and the door was open a little and we searched everywhere and we found nothing. A couple days earlier I heard the floor creak in the corner then closer then back in the corner then the floor creaked in four different places I was alone in the living room then I just ignored it with a occasional creak, this door opening really got me thinking I got 2 dogs but their Chihuahuas and I been thinking maybe it was them. Can you give me more ideas to help rationalize all this