Hi @splicedjunkie ,
Hard to tell without a screenshot, but let me try:
My guess would be, that you have 2 Objects (not 1), that are both in Edit Mode and that you are trying to connect Vertices of both Objects and that is not possible in Blender. What happens now, is that Blender only uses F on the 1 Vertex of the Active Object and that is when Blender makes a Face from that Vertex. Depending on whether you have the F2 Addon enabled (which you should imho), it will create a Triangle or a Quad:

So, what you would have to do is first combine the 2 Objects and then connect (Fill) the 2 Vertices.
Switch to Object Mode. (You should now have 2 Objects Selected.)
CTRL+J to join the Selected Object with the Active one.
Back into Edit Mode and try again.