Sleepwalking?

I think I've been sleepwalking. Not just wandering around the house like a zombie sleepwalking, I'm talking about actually doing stuff while asleep and then not remembering doing it. Since I live alone with only the cat (isn't she gorgeous?) as a witness I have no way of knowing for absolute certain. The evidence that is leading me to suspect my sleepwalking is compelling. About a week ago when I woke up in the morning I discovered the lid on the toilet was up. Now, at the time I blew it off. "I must have just neglected to put the lid down when I used the toilet before bed," I told myself. But it bothered me. I never forget to put the lid down, it's a long time habit. A few days after that I wandered into the living room after getting up in the morning to find three neat stacks of books on the coffee-table. I am one hundred percent sure that these books were neatly put away on the bookcases that line my living room walls before I went to bed.
At this point I was convinced that someone was sneaking into my apartment to use the toilet and read my books while I was sleeping. Even though I always make sure that my apartment is locked up tight before I go to bed and I'm a terribly light sleeper I was sure that these abnormalities were being caused by an outside source. So the next few nights I placed a chair in front of the door to the hallway and hung bells on the curtain that covers the sliding glass door onto the patio. No abnormalities and no ringing bells or falling chairs.
By last night I had decided that maybe I was going crazy and had imagined everything. But I was still taking the precautions of chairs and bells, just in case. This morning there were, once again, books stacked on the coffee-table and there was a yummy looking ham sandwich on the counter in the kitchen. The ham was warm, so I think that it had been laying there for a few hours. Also, this morning I had no clothes on. I went to bed in a t-shirt and sweatpants, I woke up naked.
I'm exhausted, and I've been feeling unusually stressed lately. So much work and school with no days off has started bogging me down. I haven't been reading as much as I usually do, and obviously that is starting to get to me (the stacks of books on the coffee-table is probably a hint from my subconscious mind). I'm going to try to do more reading, and cut back a little on the stress (I'm not sure how yet) and we'll see if that helps with the sleepwalking.

As a thank you for letting me ramble here's a cute sleepwalking video I found on YouTube: