If Vlookup referencing column title :)

Hello!

I have data in two tabs and need to enter an if_vlookup formula in one cell, referencing the title of a column on the next tab:

TAB1
JAN
Austria 4,444
Belgium 4,022
Denmark 1,341


TAB2

JAN FEB
Austria 4,444 5,555
Belgium 4,022 3,553
Denmark 1,341 1,009

I want to enter a vlook up on TAB1, where the data (4,444 on the example) will be updated depending on the title of the column. In this case it says JAN, next month when I change the title on TAB1 to FEB, I want the figure to be updated to 5.,555.
TAB 2 has fixed data, unchangable. I need to update the data only in TAB1

I have the impresion this is an If Vlook up, but can't find the correct way to write it...

ANY HELP WITH THIS WILL BE VERY VERY APPRECIATED