I left the house and visited my aunt and only checked normal stuff once

I went out while my partner was gone for a walk and I only checked that the dryer was done with its cycle. I'd been doing laundry all day. I checked the stove because I had just been cooking for supper. I also checked that I had turned off my laptop. I knew that the cat was upstairs.
And I left. I didn't remember locking the kitchen door because my hands were full of bags of stuff that I was giving away. I walk back 3 steps and jiggled the door handle lightly. yes, lightly because we had to replace a door handle because I would roughhouse it to make sure that the door was locked.