Ink is out eventhough there is ink in there!

So, I just changed one of the ink (yellow) for my epson r1800. After I changed it, normally the blinking red would go away, this time, it didin't blink or go away, the red light just sits there. And when I tried to print, it says that ink is out but I just changed the ink!!! I don't know what to do now. 
I bought the ink from catridge world, one of those refill ones. I don't know if this matters. I used some inks from them before and it works perfectly fine. So, I don't know what is the problem. Please help me. I have stuff due tomorrow :( Thanks so much.
grace.