It did it AGAIN!!!

I had this nicely put-together list...and even when I previewed it, the whole thing looked really nice. But then I publish, and I get 1 big paragraph...1 big run-on sentence. DO YOU KNOW HOW IRRITATING THAT IS?!?!?!?! Does anyone have any suggestions? Am I doing something wrong? Obviously I'm doing SOMETHING wrong, but what? This is (again, obviously) beyond the extent of my computer knowledge. AAHHHHHHHHHHH!!!!!!!!!!!!1