What do I do if I think I might have been sleep walking?

I had the weirdest experience today… I set my alarm last night, and went to sleep in my bed. Then this morning woke up on the couch, with the front door open. I was so confused when I realized where I was and what it must mean. Even more disturbing, my front door has been open 2 times in the last few weeks when I come out of my room in the morning. Originally I just thought I was being an idiot and forgot to close the door completely the night before, but now with this most recent experience I’m worried that I’ve actually been sleep walking around my apt at night. I live alone, so no one is gunna end up waking up and stopping me from doing… IDK, whatever it is I might be doing when this happens.

LOL! The fact that the door was open today must mean I went outside in my boxers last night. It’s all pretty hilarious really… But I don’t want to end up setting my apt on fire trying to toast a paper towel or something crazy sh*t.

I’ve never sleep walked before, that I know of, and I haven’t been doing anything different than I normally do… I don’t get drunk before bed, I don’t take sleeping pills, and I don’t feel really stressed right now.

Tonight I’m going to tie a string around my ankle and anchor it to the bedroom door, just in case. But I’m not going to do that forever so I need a more permanent solution to: 1) find out if I am in fact sleep walking, and how much, 2) how to prevent it.

How do you deal with/cure sleep walking?