Formula for Day of the Week X amount of weeks in the past from a target Date

I am looking for 1 formula that can do the following;

If cell has a date stamp that falls on the following days then it would equal to

Monday = Previous Tuesday (or 6 days ago)

Tuesday = Previous Tuesday (7 days ago)

Wednesday = 2 Tuesdays back (8 days ago)

Thursday = 2 Tuesdays back (9 days ago)

Friday = Previous Tuesday (or 3 days ago) 

Saturday = Previous Tuesday (4 days ago)

Sunday = Previous Tuesday (5 days ago) 

Currently using the following:

=$I$27-WEEKDAY($I$27+4)-(7*(WEEKDAY($I$27)=5))

...which is not working for the Wednesdays & Thursdays.  Can someone help with what needs amending to make the above work for me?