Because chapter eight is finished! I feel a bit better about it now. I think that when I was working on it yesterday I wasn't in the right frame of mind. A lot of other thoughts were crammed into my head at the time and I think that was my problem -- I couldn't concentrate properly on my characters.
Anyway -- I've broken another barrier, and am now past the 30,000 mark. I can't believe that 50% is looming ever closer on my tally bar (as it stands at the time of writing). Once I get past that point, I'll start thinking of myself as being on the home stretch. That's when it'll get scary and I'll have to start thinking about things like the last sentence. Oh yes, and something else that would help -- a proper title.