Again

I've just spent an hour on the sofa. I was thinking lucidly throughout, and I could hear the sound of people talking in the street, as well as the sound of engines revving up in the garage opposite. When I sat up I felt like I'd just woken up. It's just like yesterday, where I'm not sure if I'd slept or not. I feel very tired. I asked my brother if he had experienced anything similar, and he said he had, and he calls it 'half sleep'.