I feel really stupid

I signed up for clickworker and did my first test/assignment (classifying fashion items/clothes). After I passed the 10 question assignment it started me on the paid assignment. The problem is it's not ending!
If I click menu it tells me that if I quit I'll loose the money/assignment I'm working on.
I don't mind doing it, I've made almost a $1 (which is not much but it's my first assignment so I don't mind) but I can't do this for the rest of the day. Am I just being very dense? How long do these assignments usually last (I've probably categorized 50 items so far.)

Thanks! (from a newbie)