Today is 13 days of the Omer: Yesod of Gevurah: foundation in discipline or strength.
To be strong we must have a foundation, like a house, but a house that is built on a weak foundation will crumble and fall. Without a foundation our strength will be weak.
Yesod (foundation) is calling on us to take care of ourselves and be the best that we can be.
Today is 13 days, which are one week and six days, of the Omer.