Lost my Application Stack

So I'm not sure how this happened, but on the right side of my dock I have the Documents stack and the Downloads stack, but the Applications stack is gone. I tried to fix this by simply opening up a finder window and dragging applications from the left menu to the dock, and now that whole applications menu has disappeared as well. Any ideas how to get this back?

Thanks

EDIT: Ok I got the applications menu back into the sidebar of finder, but how do I get the stack back in the right side of my dock?

Go to your root directory (open up "Macintosh HD" on your Desktop assuming you didn't change the name). With this open, you should see an Applications folder. Drag that to the dock.