I'm sorry, my mistake on the gyn. As far as getting checked for any diseases, I was just saying that with all the reasons you stated why it was doubtful you could have gone out and come back in it seems more likely it was a dream. However, sleepwalkers can perform intricate activities, such as cooking a meal and driving a car. If you still feel this actually happened and you feel it's appropropriate, get checked out and put your mind at ease.
GYN? isn't that for pregnancy? I'm male. But why not check for any deaseases?
I don't want to risk leading you wrong, as it is only my opinion, but considering all you've said, I would not worry about getting checked for diseases any more than you normally would. Are you on any medications that cause sleep activity with amnesia? Some sleep meds in particular are known for this. But even then, with amnesia you wouldn't remember it. A dream like this can be quite unsettling. If you are still worried it would not hurt to keep putting something where you would know if you had gone out during sleep. And if you'd feel better, get a GYN checkup.
I have had no history of sleep walking, but I have put a CD close to the door, so I would know if someone opened the door. The CD would have course drop if the door had been open. But I think if I were to actually go outside it would be quite impossible to get myself back in because I don't carry any keys. And I would need to get pass the stairs. I found myself back in bed, sleeping in the same position. Without guidance. But in the worst case scenario do you think I should get a STD/HIV check?
Could it happen - yes. More likely it was a dream - yes. Do you have a history of sleepwalking? It's doubtful a first episode of sleepwalking would be to such an extreme if there's no history of it. If a person is a sleep walker, they can do quite elaborate things in their sleep. And there are some meds that have sleep activity as a side effect.
If you want to know if you are getting up during the night, find some ways to test yourself, like maybe sprinkle powder on the floor in front of the door, put lipstick on the doorhandle, whatever you can think of.
A person who is known to be a sleepwalker needs to seriously figure out ways to protect both themselves and others from their sleep activity, and not wait for a crisis to take it seriously. (Have had some family experience.)