I'm new to blender so I'm sorry if this is a noob question. Here is an example of what I want to happen when I click and drag the face along the Y axis (represented by the green arrow):
However, two extra faces appear when I try to drag along the y-axis:
Here's the face I'm stretching along the Y-axis:
Any help at all on this would be greatly appreciated. If you need more information I'd be happy to give it to you. Thank you all!