Comparing dates as IF condition (empty cell not recognized)

Hi,

I'm trying to write a formula that would check the value in cell M2 and compare it to current year and week. The cell value is in format "2015-15" (year and week number). If M2 is in the future, it should say that work is in progress, if not, a long long formula will follow (which is working, I tried it separately). What I've tried so far is this:

=IF(AND(VALUE(MID(M2;6;2))>=(WEEKNUM(TODAY();2));VALUE(LEFT(M2;4))=(YEAR(TODAY())));"In progress";../rest of the formula/..)

The problem is that the cell M2 could also be empty and then it should go on with "the rest of the formula" because the IF condition is not true, but it doesn't recognize an empty cell. I'm guessing it has something to do with the MID() part of it, because I'm telling the cell should have at least 6 characters in it. But I figured if the condition is not true, it would still go on with the formula, but it won't.

Any ideas why this isn't working or how I should compare the dates?
Thanks in advance :)

Wow, that was fast.

I tried
=IF(AND(M2<>"",M2>YEAR(TODAY())&"-"&(RIGHT("0"&WEEKNUM(TODAY()),2))),"Work in progress","rest of formula")

It seems to work as long as the cell M2 is empty, year is in the past (eg 2014-35) or year and week are in the future (eg 2015-35). It doesn't work though when it's this year but in the past (eg 2015-2), then it tells me that work is in progress, though it shouldn't.

Thanks so much