Nested If Help

Nested If Help

I'm writing this nested IF statement and it doesn't seem to be working.

Basically it will take the day of the week in number form and add a certain amount of days to another date column based on what day of the week it is.

It works as a single if statement:

If("Day of Week(Sun 1 - Sat 7)"=1, adddate("8 Week Mark",1),"8 Week Mark")

But not as a nested if:

If("Day of Week(Sun 1 - Sat 7)"=1,adddate("8 Week Mark",1),
If("Day of Week(Sun 1 - Sat 7)"=2,adddate("8 Week Mark",0),
If("Day of Week(Sun 1 - Sat 7)"=3,adddate("8 Week Mark",6),
If("Day of Week(Sun 1 - Sat 7)"=4,adddate("8 Week Mark",5),
If("Day of Week(Sun 1 - Sat 7)"=5,adddate("8 Week Mark",4),
If("Day of Week(Sun 1 - Sat 7)"=6,adddate("8 Week Mark",3),
If("Day of Week(Sun 1 - Sat 7)"=7,adddate("8 Week Mark",2,"8 Week Mark"))))))))

Please help!