Thanks to Mary, I now know that the codes I found in my notebook were Morse Code. I'm not all that savvy when it comes to things like that, but I am capable of using google and so I found a site that would translate the codes for me.
And what I found was... very, very curious, indeed.
The first code translates into; SEEYOU
What am I supposed to make out of that? It certainly seems like something one would say while sleep walking, I suppose. It doesn't make much sense.
The second batch of Morse Codes were a little different and it took me a while to translate them, mostly because I had to translate them twice. You see, the Morse Code translated into binary, which I had to translate too.
This is what it translated into; the trees
If this has been written by me (I've all ready dismissed the idea that it could've been written by anyone else in the house, which is my parents, since they're not the kind of people who would joke around like this. They're rather humourless, besides, their English isn't very good, so if they would pull a prank they would've used Swedish instead), at least 'the trees' makes a little more sense than SEEYOU. I've been thinking about going out to take some pictures, preferably of some birds if I can, but I haven't been able to do so yet, so it could be referring to that.
Anyway, I will take this as a sign from my subconscious and get my hands on the family's digital camera as soon as I can. =P