Help!

I am creating a large lookup formula but am having trouble writing one piece of it using MATCH.

Sheet1 has the following:

Cells A1 through C1 = "Week 1", "Week 2", "Week 3" respectively.
Cells A2 through C2 = Manual input area; Options are either "F" (forecast) or "A" (actual)

Sheet2 has the following:

Cells A1 through C1 = "Week 1", "Week 2", "Week 3" respectively
Cells A2 through C2 = "F" in each cell

Cells D1 through F1 = "Week 1", "Week 2", "Week 3" respectively
Cells D2 through F2 = "A" in each cell

In Sheet1, I want to reference on row 3 the position of the data I enter on row 2.

Example: In Sheet1, I enter an "F" in A2.
My formula on cell A3 is: =MATCH(A1&A2,Sheet2!A1:F1&Sheet2!A2:F2,0)

Desired result is 1
If I enter "A" instead of "F", desired result is 4

Instead I get #VALUE!

Where am I going wrong?