ruuunneeescaaappeeee!?

So every time I try to buy or sell something on the Ge, the screen won't work. Like, when I click "Sell Item" , the next screen with the price of the item and all that won't show up. I'm just sitting there clicking sell over and over again and nothing happens. Although the search bar pops up on the chatbox when I click Buy Item, but the screen with the actual price & quantity of the item won't show up. Is it lag or what?

I have a Macbook Pro, if that helps any.